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Sample records for extremity tld system

  1. Microprocessor controlled portable TLD system

    NASA Technical Reports Server (NTRS)

    Apathy, I.; Deme, S.; Feher, I.

    1996-01-01

    An up-to-date microprocessor controlled thermoluminescence dosemeter (TLD) system for environmental and space dose measurements has been developed. The earlier version of the portable TLD system, Pille, was successfully used on Soviet orbital stations as well as on the US Space Shuttle, and for environmental monitoring. The new portable TLD system, Pille'95, consists of a reader and TL bulb dosemeters, and each dosemeter is provided with an EEPROM chip for automatic identification. The glow curve data are digitised and analysed by the program of the reader. The measured data and the identification number appear on the LED display of the reader. Up to several thousand measured data together with the glow curves can be stored on a removable flash memory card. The whole system is supplied either from built-in rechargeable batteries or from the mains of the space station.

  2. Implementing a new TLD system

    SciTech Connect

    Rhea, T.A.

    1988-01-01

    Martin Marietta Energy Systems will soon be issuing new personnel dosimeters at four of their five Department of Energy (DOE) facilities, The Piketon, Ohio uranium enrichment facility is not included in this dosimetry upgrade program. This talk will focus on the ORNL perspective of this program, especially the new beta-gamma dosimeter. Neutron dosimetry will be discussed briefly. The objective of this upgrade is to put in place a state-of-the-art personnel dosimetry system and to meet the recent DOE Laboratory Accreditation Program performance criteria. Processing such a large number of dosimeters will require stringent quality controls. Approximately 18,000 beta-gamma dosimeters are scheduled for issue in January 1989. 15 figs.

  3. Dose measurements in space by the Hungarian Pille TLD system.

    PubMed

    Apathy, I; Deme, S; Feher, I; Akatov, Y A; Reitz, G; Arkhanguelski, V V

    2002-10-01

    Exposure of crew, equipment, and experiments to the ambient space radiation environment in low Earth orbit poses one of the most significant problems to long-term space habitation. Accurate dose measurement has become increasingly important during the assembly (extravehicular activity (EVA)) and operation of space stations such as on Space Station Mir. Passive integrating detector systems such as thermoluminescent dosemeters (TLDs) are commonly used for dosimetry mapping and personal dosimetry on space vehicles. The well-known advantages of passive detector systems are their independence of power supply, small dimensions, high sensitivity, good stability, wide measuring range, resistance to environmental effects, and relatively low cost. Nevertheless, they have the general disadvantage that for evaluation purposes they need a laboratory or large--in mass and power consumption--terrestrial equipment, and consequently they cannot provide time-resolved dose data during long-term space flights. KFKI Atomic Energy Research Institute (KFKI AEKI) has developed and manufactured a series of thermoluminescent dosemeter systems for measuring cosmic radiation doses in the 10 microGy to 10 Gy range, consisting of a set of bulb dosemeters and a compact, self-contained, TLD reader suitable for on-board evaluation of the dosemeters. By means of such a system, highly accurate measurements were carried out on board the Salyut-6, -7 and Mir Space Stations as well as on the Space Shuttle. A detailed description of the system is given and the comprehensive results of these measurements are summarised. c2002 Elsevier Science Ltd. All rights reserved.

  4. Evaluation of Effective Sources in Uncertainty Measurements of Personal Dosimetry by a Harshaw TLD System.

    PubMed

    Hosseini Pooya, Sm; Orouji, T

    2014-06-01

    The accurate results of the individual doses in personal dosimety which are reported by the service providers in personal dosimetry are very important. There are national / international criteria for acceptable dosimetry system performance. Objective : In this research, the sources of uncertainties are identified, measured and calculated in a personal dosimetry system by TLD. These sources are included; inhomogeneity of TLDs sensitivity, variability of TLD readings due to limited sensitivity and background, energy dependence, directional dependence, non-linearity of the response, fading, dependent on ambient temperature / humidity and calibration errors, which may affect on the dose responses. Some parameters which influence on the above sources of uncertainty are studied for Harshaw TLD-100 cards dosimeters as well as the hot gas Harshaw 6600 TLD reader system. The individual uncertainties of each sources was measured less than 6.7% in 68% confidence level. The total uncertainty was calculated 17.5% with 95% confidence level. The TLD-100 personal dosimeters as well as the Harshaw TLD-100 reader 6600 system show the total uncertainty value which is less than that of admissible value of 42% for personal dosimetry services.

  5. Evaluation of Effective Sources in Uncertainty Measurements of Personal Dosimetry by a Harshaw TLD System

    PubMed Central

    Hosseini Pooya, SM; Orouji, T

    2014-01-01

    Background: The accurate results of the individual doses in personal dosimety which are reported by the service providers in personal dosimetry are very important. There are national / international criteria for acceptable dosimetry system performance. Objective: In this research, the sources of uncertainties are identified, measured and calculated in a personal dosimetry system by TLD. Method: These sources are included; inhomogeneity of TLDs sensitivity, variability of TLD readings due to limited sensitivity and background, energy dependence, directional dependence, non-linearity of the response, fading, dependent on ambient temperature / humidity and calibration errors, which may affect on the dose responses. Some parameters which influence on the above sources of uncertainty are studied for Harshaw TLD-100 cards dosimeters as well as the hot gas Harshaw 6600 TLD reader system. Results: The individual uncertainties of each sources was measured less than 6.7% in 68% confidence level. The total uncertainty was calculated 17.5% with 95% confidence level. Conclusion: The TLD-100 personal dosimeters as well as the Harshaw TLD-100 reader 6600 system show the total uncertainty value which is less than that of admissible value of 42% for personal dosimetry services. PMID:25505769

  6. Long-term stability of a TLD-based individual monitoring system.

    PubMed

    Alves, J G; Abrantes, J N; Margo, O; Rangel, S; Santos, L

    2006-01-01

    The thermoluminescence dosemeter (TLD) system at the Individual Monitoring Service (IMS) of the Nuclear Technology Institute (ITN) at the Radiological Protection and Nuclear Safety Department (DPRSN) comprises two 6600 Harshaw readers and the Harshaw 8814 TL card and the holder containing two LiF:Mg,Ti (TLD-100) dosemeters for the evaluation of H(p)(10) and H(p)(0.07). The readers are calibrated on a monthly basis and as part of the quality assurance programme implemented at the IMS a set of dosemeters is issued monthly to the DPRSN's Standard Dosimetry Laboratory for linearity measurements. The results obtained since November 2001 are presented. Fading and sensitivity change experiments are carried out every month covering 8 week periods so that enough time is given to simulate issuing, integrating and receiving times and respective delays. A set of 96 dosemeters organised in eight subsets of 12 are used. In each subset, four dosemeters are irradiated and stored at room temperature (RT), four are not irradiated at all and the last four are irradiated after storage. The 12 dosemeters of each subset are readout at the same time, one per week, covering the 8 week period. The results from the sets irradiated and stored at different periods allowed for the evaluation of fading and sensitivity changes experienced over the whole monitoring period and respective preparation time and readout delays. Time evolution charts of the reader calibration factors, of the linearity parameters and of the evolution of the integrated area in the region of dosimetric interest with storage at RT were obtained. This paper aims to quantify the long-term stability of the TLD system in use at the IMS.

  7. A study on the behaviour of TLD-100 glow peaks at extreme ambient temperatures in Riyadh, Saudi Arabia.

    PubMed

    Al-Haj, Abdalla N; Lagarde, Charlie S

    2006-01-01

    In this study, the temperature-induced variations in the TLD-100 response and the modifications in its glow peaks are investigated in real environmental exposure conditions in Riyadh, Saudi Arabia, where ambient temperatures during summer reach >45 degrees C and with relative humidity of <10%. Three groups of 12 TLD-100 cards in Harshaw type 8814 TLD cardholders were deployed as environmental dosemeters for a period of approximately 1 month for 12 consecutive months. One group was irradiated to 5 mGy 137Cs prior to deployment; another was irradiated to the same dose after deployment, while the last group was left unirradiated. Analysis of glow curves was done using commercially available glow curve deconvolution software (CGCD). Monthly variations in peak 3, 4 and 5 areas relative to the corresponding peak areas of a prompt glow curve are presented. Results of this study show good TL signal compensation between peaks 4 and 5 at all ambient temperatures encountered in this experiment, despite the observed individual variations experienced by each of these peaks. The sum of peak 4 and 5 areas is constant to within approximately 10%, for both pre- and post-irradiated dosemeters, during this 12-month cycle.

  8. A whole-body dosimetry system for personal monitoring based on hot-pressed thin layer TLD.

    PubMed

    Busch, F; Engelhardt, J; Martini, E; Lesz, J

    2011-03-01

    We are introducing a new high-capacity thermoluminescent dosemeter (TLD) system to measure the whole body values of H(p)(10) and H(p)(0.07) from photons for use in individual monitoring services. Small and light-weight badges allow a convenient application in a wide variety of workplaces with photon radiation from 20 keV to at least 7 MeV. The main advantage of this system will be the large capacity of ∼ 100,000 dosemeters per month at costs equivalent to the current film monitoring. The hot-pressed thin-layer TL detector (LiF:Mg,Ti) is welded onto an aluminium substrate and provided with a data matrix code for automatic processing. The detector holder has been optimised, that no additional filter is necessary. The new designed TLD reader with readout times <10 s will allow a large throughput and a considerable degree of automation.

  9. Performance testing of the environmental TLD system for the Three Mile Island Nuclear Station.

    PubMed

    Toke, L F; Carson, B H; Baker, G G; McBride, M H; Plato, P A; Miklos, J A

    1984-05-01

    Panasonic UD-801 thermoluminescent dosimeters ( TLDs ) containing two calcium sulfate phosphors were tested under Performance Specification 3.1 established by the American National Standard Institute ( ANSI75 ) and in the U.S. Nuclear Regulatory Commission's Regulatory Guide 4.13 ( NRC77 ). The specific qualifying tests included TLD uniformity, reproducibility, energy dependence and directional dependence. The overall measurement uncertainties and associated confidence levels are within the prescribed guidelines defined in the qualifying requirements for environmental TLDs .

  10. Lateral vibration behavior analysis and TLD vibration absorption design of the soft yoke single-point mooring system

    NASA Astrophysics Data System (ADS)

    Lyu, Bai-cheng; Wu, Wen-hua; Yao, Wei-an; Du, Yu

    2017-06-01

    Mooring system is the key equipment of FPSO safe operation. The soft yoke mooring system is regarded as one of the best shallow water mooring strategies and widely applied to the oil exploitation in the Bohai Bay in China and the Gulf of Mexico. Based on the analysis of numerous monitoring data obtained by the prototype monitoring system of one FPSO in the Bohai Bay, the on-site lateral vibration behaviors found on the site of the soft yoke subject to wave load were analyzed. ADAMS simulation and model experiment were utilized to analyze the soft yoke lateral vibration and it was determined that lateral vibration was resonance behaviors caused by wave excitation. On the basis of the soft yoke longitudinal restoring force being guaranteed, a TLD-based vibration damper system was constructed and the vibration reduction experiments with multi-tank space and multi-load conditions were developed. The experimental results demonstrated that the proposed TLD vibration reduction system can effectively reduce lateral vibration of soft yoke structures.

  11. SU-E-T-594: Out-Of-Field Neutron and Gamma Dose Estimated Using TLD-600/700 Pairs in the Wobbling Proton Therapy System

    SciTech Connect

    Chen, Y; Lin, Y; Tsai, H

    2015-06-15

    Purpose: Secondary fast neutrons and gamma rays are mainly produced due to the interaction of the primary proton beam with the beam delivery nozzle. These secondary radiation dose to patients and radiation workers are unwanted. The purpose of this study is to estimate the neutron and gamma dose equivalent out of the treatment volume during the wobbling proton therapy system. Methods: Two types of thermoluminescent (TL) dosimeters, TLD-600 ({sup 6}LiF: Mg, Ti) and TLD-700 ({sup 7}LiF: Mg, Ti) were used in this study. They were calibrated in the standard neutron and gamma sources at National Standards Laboratory. Annealing procedure is 400°C for 1 hour, 100°C for 2 hours and spontaneously cooling down to the room temperature in a programmable oven. Two-peak method (a kind of glow curve analysis technique) was used to evaluate the TL response corresponding to the neutron and gamma dose. The TLD pairs were placed outside the treatment field at the neutron-gamma mixed field with 190-MeV proton beam produced by the wobbling system through the polyethylene plate phantom. The results of TLD measurement were compared to the Monte Carlo simulation. Results: The initial experiment results of calculated dose equivalents are 0.63, 0.38, 0.21 and 0.13 mSv per Gy outside the field at the distance of 50, 100, 150 and 200 cm. Conclusion: The TLD-600 and TLD-700 pairs are convenient to estimate neutron and gamma dosimetry during proton therapy. However, an accurate and suitable glow curve analysis technique is necessary. During the wobbling system proton therapy, our results showed that the neutron and gamma doses outside the treatment field are noticeable. This study was supported by the grants from the Chang Gung Memorial Hospital (CMRPD1C0682)

  12. A robotic manipulator for handling TLD badges.

    PubMed

    Levinson, S; Weinstein, M; Abraham, A; German, U; Gorelik, V; Rozenfeld, R; Hillel, S; Rodnay, G

    2008-11-01

    A prototype system for automatic handling of Harshaw/Bicron (now ThermoFisher Scientific) thermoluminescent dosimetry (TLD) badges, which is based on a robotic arm, was designed and built. The robot performs the loading and unloading of the TLD cards in the badges and transports them between the loading/unloading station and magazine stations. For quality assurance, a sticker containing the worker's details printed in barcode format was added to the badge. Automatic on-line identification is performed for checking the correlation between the badge and the TLD card number.

  13. Doses due to the South Atlantic Anomaly during the Euromir'95 mission measured by an on-board TLD system.

    PubMed

    Deme, S; Reitz, G; Apathy, I; Hejja, I; Lang, E; Feher, I

    1999-01-01

    During the Euromir'95 mission, a specially designed microprocessor-controlled thermoluminescent detector (TLD) system, called the 'Pille'95', was used by ESA astronaut Thomas Reiter to measure the cosmic radiation dose inside the Mir space station. One of the experiment's objectives was to determine the dose fraction on Mir due to the South Atlantic Anomaly (SAA) on an orbit inclined at 51.6 degrees and at an altitude of about 400 km. Using an hourly measuring period for 170 h in automatic mode, dose components both of galactic (independent of SAA) and SAA origin were determined. It was found that the maximum dose due to crossing the SAA was equal to 55 microGy. Averaging all the measurements it was calculated that the mean dose rate inside the Mir was 12-14 microGy h-1 and that half of this value was caused by the SAA.

  14. Extra dose due to extravehicular activity during the NASA4 mission measured by an on-board TLD system

    NASA Technical Reports Server (NTRS)

    Deme, S.; Apathy, I.; Hejja, I.; Lang, E.; Feher, I.

    1999-01-01

    A microprocessor-controlled on-board TLD system, 'Pille'96', was used during the NASA4 (1997) mission to monitor the cosmic radiation dose inside the Mir Space Station and to measure the extra dose to two astronauts in the course of their extravehicular activity (EVA). For the EVA dose measurements, CaSO4:Dy bulb dosemeters were located in specially designed pockets of the ORLAN spacesuits. During an EVA lasting 6 h, the dose ratio inside and outside Mir was measured. During the EVA, Mir crossed the South Atlantic Anomaly (SAA) three times. Taking into account the influence of these three crossings the mean EVA/internal dose rate ratio was 3.2. Internal dose mapping using CaSO4:Dy dosemeters gave mean dose rates ranging from 9.3 to 18.3 microGy h-1 at locations where the shielding effect was not the same. Evaluation results of the high temperature region of LiF dosemeters are given to estimate the mean LET.

  15. Extra dose due to extravehicular activity during the NASA4 mission measured by an on-board TLD system

    NASA Technical Reports Server (NTRS)

    Deme, S.; Apathy, I.; Hejja, I.; Lang, E.; Feher, I.

    1999-01-01

    A microprocessor-controlled on-board TLD system, 'Pille'96', was used during the NASA4 (1997) mission to monitor the cosmic radiation dose inside the Mir Space Station and to measure the extra dose to two astronauts in the course of their extravehicular activity (EVA). For the EVA dose measurements, CaSO4:Dy bulb dosemeters were located in specially designed pockets of the ORLAN spacesuits. During an EVA lasting 6 h, the dose ratio inside and outside Mir was measured. During the EVA, Mir crossed the South Atlantic Anomaly (SAA) three times. Taking into account the influence of these three crossings the mean EVA/internal dose rate ratio was 3.2. Internal dose mapping using CaSO4:Dy dosemeters gave mean dose rates ranging from 9.3 to 18.3 microGy h-1 at locations where the shielding effect was not the same. Evaluation results of the high temperature region of LiF dosemeters are given to estimate the mean LET.

  16. Extra dose due to extravehicular activity during the NASA4 mission measured by an on-board TLD system.

    PubMed

    Deme, S; Apathy, I; Hejja, I; Lang, E; Feher, I

    1999-01-01

    A microprocessor-controlled on-board TLD system, 'Pille'96', was used during the NASA4 (1997) mission to monitor the cosmic radiation dose inside the Mir Space Station and to measure the extra dose to two astronauts in the course of their extravehicular activity (EVA). For the EVA dose measurements, CaSO4:Dy bulb dosemeters were located in specially designed pockets of the ORLAN spacesuits. During an EVA lasting 6 h, the dose ratio inside and outside Mir was measured. During the EVA, Mir crossed the South Atlantic Anomaly (SAA) three times. Taking into account the influence of these three crossings the mean EVA/internal dose rate ratio was 3.2. Internal dose mapping using CaSO4:Dy dosemeters gave mean dose rates ranging from 9.3 to 18.3 microGy h-1 at locations where the shielding effect was not the same. Evaluation results of the high temperature region of LiF dosemeters are given to estimate the mean LET.

  17. Use of a TLD-based multisphere spectrometry system to measure the neutron spectra around a not-self-shielded PET cyclotron: Preliminary results.

    PubMed

    Guimarães, A M; Lacerda, M A S; Santos, J A L; Maletta, P G M; Rodrigues, S L M; Andrade, R S; Vilela, E C; da Silva, T A

    2012-12-01

    In the present work, we utilized the BSS system with TLD-600 and TLD-700 to measure the neutron spectra around the GE-PETtrace 8 cyclotron of the Development Centre of Nuclear Technology (CDTN/CNEN) in Belo Horizonte, Brazil. The cyclotron is capable of accelerating protons up to 16.5 MeV, to production of fluorine-18. Four points inside the bunker of the cyclotron were studied. Two points in front of the primary radiation beam and other two opposed to the primary radiation beam. The measurements were unfolded with the BUMS and the NSDUAZ computer codes. The dosimetric quantities obtained were in agreement with the other published data and were coherent with the expected from theoretical estimates obtained from source term informed by the manufacturer of the cyclotron.

  18. Intensity variation study of the radiation field in a mammographic system using thermoluminescent dosimeters TLD-900 (CaSO4:Dy)

    NASA Astrophysics Data System (ADS)

    Corrêa, E. L.; Silva, J. O.; Vivolo, V.; Potiens, M. P. A.; Daros, K. A. C.; Medeiros, R. B.

    2014-02-01

    This study presents the results of the intensity variation of the radiation field in a mammographic system using the thermoluminescent dosimeter TLD-900 (CaSO4:Dy). These TLDs were calibrated and characterized in an industrial X-ray system used for instruments calibration, in the energy range used in mammography. They were distributed in a matrix of 19 lines and five columns, covering an area of 18 cm×8 cm in the center of the radiation field on the clinical equipment. The results showed a variation of the intensity probably explained by the non-uniformity of the field due to the heel effect.

  19. Calibration of a TLD-100 powder dosimetric system to verify the absorbed dose to water imparted by 137Cs sources in low dose rate brachytherapy at the oncology unit in the Hospital General de Mexico.

    PubMed

    Alvarez Romero, J T; Tovar Muñoz, V M; de León, B Salinas; Oviedo, J O Hernández; Barcenas, L Santillán; Milo, C Molero; Monterrubio, J Montoya

    2006-01-01

    A thermoluminescence dosimetry (TLD) system was characterised at SSDL-ININ to verify the air-kerma strength (S(K)) and dose-to-water (D(W)) values for (137)Cs sources used in low dose rate (LDR) brachytherapy treatments at the Hospital General de Mexico (HGM). It consists of a Harshaw 3500 reader and a set of TLD-100 powder capsules. The samples of TLD-100 powder were calibrated in terms of D(W) vs. nC or nC mg(-1), and their dose response curves were corrected for supralinearity. The D(W) was calculated using the AAPM TG-43 formalism using S(K) for a CDCSM4 (137)Cs reference source. The S(K) value was obtained by using a NE 2611 chamber, and with two well chambers. The angular anisotropy factor was measured with the NE 2611 chamber for this source. The HGM irradiated TLD-100 powder capsules to a reference dose D(W) of 2 Gy with their (137)Cs sources. The percent deviations between the imparted and reference doses were 1.2% < or = Delta < or = 6.5%, which are consistent with the combined uncertainties: 5.6% < or = u(c) < or = 9.8% for D(W).

  20. Optical Calibration of TLD Readers

    DTIC Science & Technology

    2007-11-02

    DISTRIBUTION CODE 13. ABSTRACT: The Navy uses thermoluminescent dosimeters (TLDs) on all of its nuclear warships. TLDs measure the amount of radiation a person...6614. SUBJECT TERMS: Nucl_______ thermoluminescent dosimeters, TLD reader, temperature compensation, laser diodes, light emitting diodes...Navy uses thermoluminescent dosimeters (TLDs) on all of its nuclear warships. TLDs measure the amount of radiation a person receives through the use

  1. Factors affecting the precision of TLD dose measurements using an automatic TLD reader.

    PubMed

    Wood, J J; Mayles, W P

    1995-02-01

    An increase in the variability of TLD dose measurements prompted a study of the precision of dose measurements with a Rialto automatic TLD reader. It was found that readings with the same chip measured using two different trays could differ by as much as 7%. In order to overcome this problem it was necessary to ensure that individual chips were correctly identified. Marking the chips with a hard graphite pencil was found to be a satisfactory method of identifying them, which, although it reduced the light output by approximately 3%, had no effect on the reproducibility of readings. Using marked chips and an individual tray for each chip, the reproducibility of a reading was reduced to a typical value of 1%. A system of quality assurance based on these findings is described.

  2. SU-E-T-87: Comparison Study of Dose Reconstruction From Cylindrical Diode Array Measurements, with TLD Measurements and Treatment Planning System Calculations in Anthropomorphic Head and Neck and Lung Phantoms

    SciTech Connect

    Benhabib, S; Cardan, R; Huang, M; Brezovich, I; Popple, R; Faught, A; Followill, D

    2014-06-01

    Purpose: To assess dose calculated by the 3DVH software (Sun Nuclear Systems, Melbourne, FL) against TLD measurements and treatment planning system calculations in anthropomorphic phantoms. Methods: The IROC Houston (RPC) head and neck (HN) and lung phantoms were scanned and plans were generated using Eclipse (Varian Medical Systems, Milpitas, CA) following IROC Houston procedures. For the H and N phantom, 6 MV VMAT and 9-field dynamic MLC (DMLC) plans were created. For the lung phantom 6 MV VMAT and 15 MV 9-field dynamic MLC (DMLC) plans were created. The plans were delivered to the phantoms and to an ArcCHECK (Sun Nuclear Systems, Melbourne, FL). The head and neck phantom contained 8 TLDs located at PTV1 (4), PTV2 (2), and OAR Cord (2). The lung phantom contained 4 TLDs, 2 in the PTV, 1 in the cord, and 1 in the heart. Daily outputs were recorded before each measurement for correction. 3DVH dose reconstruction software was used to project the calculated dose to patient anatomy. Results: For the HN phantom, the maximum difference between 3DVH and TLDs was -3.4% and between 3DVH and Eclipse was 1.2%. For the lung plan the maximum difference between 3DVH and TLDs was 4.3%, except for the spinal cord for which 3DVH overestimated the TLD dose by 12%. The maximum difference between 3DVH and Eclipse was 0.3%. 3DVH agreed well with Eclipse because the dose reconstruction algorithm uses the diode measurements to perturb the dose calculated by the treatment planning system; therefore, if there is a problem in the modeling or heterogeneity correction, it will be carried through to 3DVH. Conclusion: 3DVH agreed well with Eclipse and TLD measurements. Comparison of 3DVH with film measurements is ongoing. Work supported by PHS grant CA10953 and CA81647 (NCI, DHHS)

  3. A TLD-based ten channel system for the spectrometry of bremsstrahlung generated by laser-matter interaction

    NASA Astrophysics Data System (ADS)

    Horst, Felix; Fehrenbacher, Georg; Radon, Torsten; Kozlova, Ekaterina; Rosmej, Olga; Czarnecki, Damian; Schrenk, Oliver; Breckow, Joachim; Zink, Klemens

    2015-05-01

    This work presents a thermoluminescence dosimetry based method for the measurement of bremsstrahlung spectra in the energy range from 30 keV to 100 MeV, resolved in ten different energy intervals and for the photon ambient dosimetry in ultrashort pulsed radiation fields as e.g. generated during operation of the PHELIX laser at the GSI Helmholtzzentrum für Schwerionenforschung. The method is a routine-oriented development by application of a multi-filter technique. The data analysis takes around 1 h. The spectral information is obtained by the unfolding of the response of ten thermoluminescence dosimeters with absorbers of different materials and thicknesses arranged as a stack each with a different response function to photon radiation. These response functions were simulated by the use of the Monte Carlo code FLUKA. An algorithm was developed to unfold bremsstrahlung spectra from the readings of the ten dosimeters. The method has been validated by measurements at a clinical electron linear accelerator (6 MV and 18 MV bremsstrahlung). First measurements at the PHELIX laser system were carried out in December 2013 and January 2014. Spectra with photon energies up to 10 MeV and mean energies up to 420 keV were observed at laser-intensities around 1019 W /cm2 on a titanium foil target. The measurement results imply that the steel walls of the target chamber might be an additional bright x-ray source.

  4. Extreme Value Laws for Dynamical Systems with Countable Extremal Sets

    NASA Astrophysics Data System (ADS)

    Azevedo, Davide; Freitas, Ana Cristina Moreira; Freitas, Jorge Milhazes; Rodrigues, Fagner B.

    2017-06-01

    We consider stationary stochastic processes arising from dynamical systems by evaluating a given observable along the orbits of the system. We focus on the extremal behaviour of the process, which is related to the entrance in certain regions of the phase space, which correspond to neighbourhoods of the maximal set M, i.e.,the set of points where the observable is maximised. The main novelty here is the fact that we consider that the set M may have a countable number of points, which are associated by belonging to the orbit of a certain point, and may have accumulation points. In order to prove the existence of distributional limits and study the intensity of clustering, given by the Extremal Index, we generalise the conditions previously introduced in Freitas (Adv Math 231(5): 2626-2665, 2012, Stoch Process Appl 125(4): 1653-1687, 2015).

  5. On-board TLD measurements on MIR and ISS.

    PubMed

    Deme, S; Apáthy, I; Pázmándi, T; Benton, E R; Reitz, G; Akatov, Y

    2006-01-01

    This paper presents results from dosimetric measurements made aboard the Mir space station and the International Space Station (ISS) using the Pille portable thermoluminescent dosemeter (TLD) system. This paper includes the dosimetry mapping and automatic readout (trapped and untrapped components) results from Mir and ISS. The mean dose rate in 2001-2003 was 7 microGy h(-1). Using the hourly measuring period in automatic mode, doses from both galactic (independent of South Atlantic Anomaly--SAA) and SAA components were determined during Euromir'95 experiment. The mean total dose rate was 12.5 microGy h(-1), while the SAA contribution was 6.2 microGy h(-1). A similar measurement was performed on ISS in 2001 and in 2003. Both the manual and automatic measurements show a significant decrease in dose rate in 2001 in comparison to 1995-1997 due to the change in solar activity. For determination of the high linear energy transfer contribution from the radiation field during the ISS mapping experiment, three CR-39 plastic nuclear track detectors (PNTDs) were co-located with each TL detector. Analysis of the combined TLD and PNTD measurements showed a typical mean TLD efficiency of 84%, a dose contribution <10 keV microm(-1) of 17%, and an average quality factor of 1.95.

  6. An ultra-high dose of electron radiation response of Germanium Flat Fiber and TLD-100

    NASA Astrophysics Data System (ADS)

    Alawiah, A.; Amin, Y. M.; Abdul-Rashid, H. A.; Abdullah, W. S. Wan; Maah, M. J.; Bradley, D. A.

    2017-01-01

    The thermoluminescence (TL) response of Germanium Flat Fiber (GFF) and TLD-100 irradiated with 2.5 MeV electrons for the doses up to 1 MGy were studied and compared. The aim was to evaluate the TL supralinearity response at an ultra-high dose (UHD) range and to investigate the change in kinetic parameters of the glow peaks, as the doses increases up to 1 MGy. It is found that the critical dose limit (CDL) of GFF is 5 times higher as compared to TLD-100. CDL is determined by the dose at the maximum supralinearity, f(D)max. It is also found that annealing the TLD-100 and GFF with temperature more than 400 °C is required to reset it back to its original condition, following radiation doses up to 1 MGy. It is also noticed the strange behavior of Peak 4 (TLD-100), which tends to be invisible at the lower dose (<10 kGy) and starts to be appeared at the critical dose limit of 10 kGy. This result might be an important clue to understand the behavior of TLD-100 at extremely high dose range. For both samples, it is observed that the TL intensity is not saturated within the UHD range studied.

  7. Extreme-UV lithography system

    DOEpatents

    Replogle, William C.; Sweatt, William C.

    2001-01-01

    A photolithography system that employs a condenser that includes a series of aspheric mirrors on one side of a small, incoherent source of radiation producing a series of beams is provided. Each aspheric mirror images the quasi point source into a curved line segment. A relatively small arc of the ring image is needed by the camera; all of the beams are so manipulated that they all fall onto this same arc needed by the camera. Also, all of the beams are aimed through the camera's virtual entrance pupil. The condenser includes a correcting mirror for reshaping a beam segment which improves the overall system efficiency. The condenser efficiently fills the larger radius ringfield created by today's advanced camera designs. The system further includes (i) means for adjusting the intensity profile at the camera's entrance pupil or (ii) means for partially shielding the illumination imaging onto the mask or wafer. The adjusting means can, for example, change at least one of: (i) partial coherence of the photolithography system, (ii) mask image illumination uniformity on the wafer or (iii) centroid position of the illumination flux in the entrance pupil. A particularly preferred adjusting means includes at least one vignetting mask that covers at least a portion of the at least two substantially equal radial segments of the parent aspheric mirror.

  8. SU-E-T-308: Systematic Characterization of the Energy Response of Different LiF TLD Crystals for Dosimetry Applications

    SciTech Connect

    Pena, E; Caprile, P; Sanchez-Nieto, B

    2014-06-01

    Purpose: The thermoluminiscense dosimeters (TLDs) are widely used in personal and clinical dosimetry due to its small size, good sensitivity and tissue equivalence, among other advantages. This study presents the characterization of Lithium Fluoride based TLDs, in terms of their absorbed dose response to successive irradiation cycles in a broad range of beam energies, measured under reference conditions. Methods: Four types of Harshaw TLD chips were used: TLD-100, TLD-600 TLD-700 and 100-H. They were irradiated with 10 photon beams of different energy spectrums, from 28 kVp to 18MV (in 30 consecutive cycles for 6 and 18 MV). Results: It was found that the response of the dosimetric system was stabilized (less than ±3%) after 10 cycles for TLD-600 and TLD-700. In the case of TLD-100 and TLD-100H this dependence was not observed. A decreased response to increasing beam energy in terms of absorbed dose to water was observed, as expected, except for TLD-100H which showed the opposite behavior. The less energy dependent detector was the TLD-100H exhibiting a maximum deviation of 12%. The highest variation observed was 33% for TLD-100. The study allowed the determination of calibration factors in absorbed dose for a wide range of energies and materials for different dosimetric applications, such as in-vivo dosimetry during imaging and radiotherapy. Conclusion: The study allowed the determination of calibration factors in absorbed dose for a wide range of energies and materials for different dosimetric applications, such as in-vivo dosimetry during imaging and radiotherapy.

  9. Improvement of Accuracy in Environmental Dosimetry by TLD Cards Using Three-dimensional Calibration Method

    PubMed Central

    HosseiniAliabadi, S. J.; Hosseini Pooya, S. M.; Afarideh, H.; Mianji, F.

    2015-01-01

    Introduction The angular dependency of response for TLD cards may cause deviation from its true value on the results of environmental dosimetry, since TLDs may be exposed to radiation at different angles of incidence from the surrounding area. Objective A 3D setting of TLD cards has been calibrated isotropically in a standard radiation field to evaluate the improvement of the accuracy of measurement for environmental dosimetry. Method Three personal TLD cards were rectangularly placed in a cylindrical holder, and calibrated using 1D and 3D calibration methods. Then, the dosimeter has been used simultaneously with a reference instrument in a real radiation field measuring the accumulated dose within a time interval. Result The results show that the accuracy of measurement has been improved by 6.5% using 3D calibration factor in comparison with that of normal 1D calibration method. Conclusion This system can be utilized in large scale environmental monitoring with a higher accuracy. PMID:26157729

  10. Organ radiation exposure with EOS: GATE simulations versus TLD measurements

    NASA Astrophysics Data System (ADS)

    Clavel, A. H.; Thevenard-Berger, P.; Verdun, F. R.; Létang, J. M.; Darbon, A.

    2016-03-01

    EOS® is an innovative X-ray imaging system allowing the acquisition of two simultaneous images of a patient in the standing position, during the vertical scan of two orthogonal fan beams. This study aimed to compute organs radiation exposure to a patient, in the particular geometry of this system. Two different positions of the patient in the machine were studied, corresponding to postero-anterior plus left lateral projections (PA-LLAT) and antero-posterior plus right lateral projections (AP-RLAT). To achieve this goal, a Monte-Carlo simulation was developed based on a GATE environment. To model the physical properties of the patient, a computational phantom was produced based on computed tomography scan data of an anthropomorphic phantom. The simulations provided several organs doses, which were compared to previously published dose results measured with Thermo Luminescent Detectors (TLD) in the same conditions and with the same phantom. The simulation results showed a good agreement with measured doses at the TLD locations, for both AP-RLAT and PA-LLAT projections. This study also showed that the organ dose assessed only from a sample of locations, rather than considering the whole organ, introduced significant bias, depending on organs and projections.

  11. A TLD dose algorithm using artificial neural networks

    SciTech Connect

    Moscovitch, M.; Rotunda, J.E.; Tawil, R.A.; Rathbone, B.A.

    1995-12-31

    An artificial neural network was designed and used to develop a dose algorithm for a multi-element thermoluminescence dosimeter (TLD). The neural network architecture is based on the concept of functional links network (FLN). Neural network is an information processing method inspired by the biological nervous system. A dose algorithm based on neural networks is fundamentally different as compared to conventional algorithms, as it has the capability to learn from its own experience. The neural network algorithm is shown the expected dose values (output) associated with given responses of a multi-element dosimeter (input) many times. The algorithm, being trained that way, eventually is capable to produce its own unique solution to similar (but not exactly the same) dose calculation problems. For personal dosimetry, the output consists of the desired dose components: deep dose, shallow dose and eye dose. The input consists of the TL data obtained from the readout of a multi-element dosimeter. The neural network approach was applied to the Harshaw Type 8825 TLD, and was shown to significantly improve the performance of this dosimeter, well within the U.S. accreditation requirements for personnel dosimeters.

  12. A combined TLD/emulsion method of sampling dosimetry applied to Apollo missions

    NASA Technical Reports Server (NTRS)

    Schaefer, H. J.

    1979-01-01

    A system which simplifies the complex monitoring methods used to measure the astronaut's radiation exposure in space is proposed. The excess dose equivalents of trapped protons and secondary neutrons, protons, and alpha particles from local nuclear interactions are determined and a combined thermoluminescent dosimeter (TLD)/nuclear emulsion method which measures the absorbed dose with thermoluminescent dosimeter chips is presented.

  13. Extreme Low Frequency Acoustic Measurement System

    NASA Technical Reports Server (NTRS)

    Shams, Qamar A. (Inventor); Zuckerwar, Allan J. (Inventor)

    2017-01-01

    The present invention is an extremely low frequency (ELF) microphone and acoustic measurement system capable of infrasound detection in a portable and easily deployable form factor. In one embodiment of the invention, an extremely low frequency electret microphone comprises a membrane, a backplate, and a backchamber. The backchamber is sealed to allow substantially no air exchange between the backchamber and outside the microphone. Compliance of the membrane may be less than ambient air compliance. The backplate may define a plurality of holes and a slot may be defined between an outer diameter of the backplate and an inner wall of the microphone. The locations and sizes of the holes, the size of the slot, and the volume of the backchamber may be selected such that membrane motion is substantially critically damped.

  14. Extreme low frequency acoustic measurement system

    NASA Technical Reports Server (NTRS)

    Shams, Qamar A. (Inventor); Zuckerwar, Allan J. (Inventor)

    2013-01-01

    The present invention is an extremely low frequency (ELF) microphone and acoustic measurement system capable of infrasound detection in a portable and easily deployable form factor. In one embodiment of the invention, an extremely low frequency electret microphone comprises a membrane, a backplate, and a backchamber. The backchamber is sealed to allow substantially no air exchange between the backchamber and outside the microphone. Compliance of the membrane may be less than ambient air compliance. The backplate may define a plurality of holes and a slot may be defined between an outer diameter of the backplate and an inner wall of the microphone. The locations and sizes of the holes, the size of the slot, and the volume of the backchamber may be selected such that membrane motion is substantially critically damped.

  15. An improved TLD with Harris corner and color moment

    NASA Astrophysics Data System (ADS)

    Li, Ling; Liu, Kai; Cheng, Fei; Bao, Di

    2017-02-01

    Video tracking is a main field of computer vision, and TLD algorithm plays a key role in long-term tracking. However, the original TLD ignores the color features of patch in detection, and tracks the common points from grid, then, the tracking accuracy is limited to both of them. This paper presents a novel TLD algorithm with Harris corner and color moment to overcome this drawback. Instead of tracking common points, we screen more important points utilizing Harris corner to reject a half patches, these points are better able to show the object's textural features. In addition, the color moment classifier replaces patch variance to reduce the errors of detection. The classifier compares mine-dimensional color moment vectors so that it can keep the TLD's stable speed. Experiment has proved that our TLD tracks a more reliable position and higher ability without affecting the speed.

  16. Runtime Systems for Extreme Scale Platforms

    DTIC Science & Technology

    2013-12-01

    Nodes) 500000 O(Million) Total Concurrency 50 Million O(Billion) Storage 150 PB 300 PB I / O 10 TB/s 20 TB/s Power 10 MW 20 MW Table 1.1 : The...heterogeneous processors, non-uniform clock speeds and other load imbalances across cores due to power management, fault tolerance, and other runtime...future extreme scale systems, driven by a limited power budget, will have reduced shared-memory capacities, lead- ing to an increased focus on efficient

  17. Assessment of the dose distribution inside a cardiac cath lab using TLD measurements and Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Baptista, M.; Teles, P.; Cardoso, G.; Vaz, P.

    2014-11-01

    Over the last decade, there was a substantial increase in the number of interventional cardiology procedures worldwide, and the corresponding ionizing radiation doses for both the medical staff and patients became a subject of concern. Interventional procedures in cardiology are normally very complex, resulting in long exposure times. Also, these interventions require the operator to work near the patient and, consequently, close to the primary X-ray beam. Moreover, due to the scattered radiation from the patient and the equipment, the medical staff is also exposed to a non-uniform radiation field that can lead to a significant exposure of sensitive body organs and tissues, such as the eye lens, the thyroid and the extremities. In order to better understand the spatial variation of the dose and dose rate distributions during an interventional cardiology procedure, the dose distribution around a C-arm fluoroscopic system, in operation in a cardiac cath lab at Portuguese Hospital, was estimated using both Monte Carlo (MC) simulations and dosimetric measurements. To model and simulate the cardiac cath lab, including the fluoroscopic equipment used to execute interventional procedures, the state-of-the-art MC radiation transport code MCNPX 2.7.0 was used. Subsequently, Thermo-Luminescent Detector (TLD) measurements were performed, in order to validate and support the simulation results obtained for the cath lab model. The preliminary results presented in this study reveal that the cardiac cath lab model was successfully validated, taking into account the good agreement between MC calculations and TLD measurements. The simulated results for the isodose curves related to the C-arm fluoroscopic system are also consistent with the dosimetric information provided by the equipment manufacturer (Siemens). The adequacy of the implemented computational model used to simulate complex procedures and map dose distributions around the operator and the medical staff is discussed, in

  18. Development of a technique for improving coefficient of variation of CaSO4:Dy teflon-based TLD personnel monitoring system in low-dose region.

    PubMed

    Pradhan, S M; Sneha, C; Sahai, M K; Chougaonkar, M P; Babu, D A R

    2015-12-01

    In view of the importance of zero-dose background (null signal) in influencing the coefficient of variation in low-dose region, a technique for the estimation of the same from composite (gross) signal is developed for CaSO4:Dy-based personnel monitoring system being used in India. The technique is based on simple analysis of glow curves (GCs) of unexposed and exposed dosemeters, evolution of trend/model for the zero-dose curves, generation of simulation protocol for individual zero-dose curves, establishment of characteristics of GCs of exposed dosemeters and finally preparation of an algorithm to segregate the components from composite signal. The technique offers the separation of real-time background and gives superior results over other method of approximation of the background. The results also prove efficiency of the empirical trending and simulation protocol of background GCs. The proposed technique can be implemented in routine monitoring without any extra man hours and reader time.

  19. New thermoluminescent dosimeters (TLD): optimization and characterization of TLD threads sterilizable by autoclave.

    PubMed

    Jarnet, D; Denizot, B; Hindré, F; Venier-Julienne, M C; Lisbona, A; Bardiès, M; Jallet, P

    2004-05-07

    To improve the performance of mono-extruded TLD threads as a dosimetric thermoluminescent tool (French Patent 9903729), a new process was developed by co-extrusion methodology leading to threads of 600 microm diameter with a 50 microm homogeneous polypropylene sheath. In this optimization work, study of parameters such as LiF:Mg,Cu,P powder granulometry, load rate and proportion of components led to an increased sensitivity of around 40%. Moreover, the co-extrusion technique allowed the threads to be sterilized by humid steam (134 degrees C/18 min) without significant variation of the linearity response between 0 and 30 Gy after gamma irradiation (60Co).

  20. Thermoluminescent characteristics of new pre-calibrated dosimeters (TLD) in commercially available readers for selected applications

    NASA Astrophysics Data System (ADS)

    Tawil, R. A.; Pontikos, P.; Szalanczy, A.; Velbeck, K.; Bruml, W.; Rotunda, J. E.

    1994-12-01

    This paper reports the performance of newly developed pre-calibrated Thermoluminescent Dosimeters (TLD) with a description and performance results for two commercially available TLD readers. Introduced for use in basic research, medical diagnostics and therapy applications, the Harshaw Model 5500 Automatic TLD Reader evaluates up to 50 dosimeters (rods, chips, disks, μ-cubes) per loading; the Harshaw Model 3500 Manual TLD Reader evaluates single dosimeters and powder. Tests were conducted using the International Electrotechnical Commission (IEC) guidelines for TLD readers to determine system performance and compliance. Both instruments passed the compliance standards in all tests established by the IEC: detection thresholds for both instruments were less than 10μGy, reproducibility was better than 0.7%, sensitivity to ambient light was less than 0.2 Hmax (where Hmax is the maximum detection threshold), TL residue was less than 1% of the total integral charge, stability less than 1% deviation after a 24 hour warm-up period, linearity was within specification, test light stability was under 1%, and power leakage requirements set forth by UL-544 (less than 500 μA AC RMS leakage) was less than 42 μA AC RMS in all cases. The characteristics of newly introduced, factory calibrated, extruded TLD-100 rods were investigated by studying the consistency of the Element Correction Coefficients (ECCs) under a variety of conditions. The ECC (< x> / xi) relates an individual dosimeter's response, xi, to the mean response, < x>, of the group. Supralinearity effects and the validity of ECCs generated at 1 cGy for use in the 50-900 cGy dose range were characterized and reported. The results for two specific applications, phantom studies with 60Co and at four Orthovoltage energies are also reported. Portability of Element Correction Coefficients from reader to reader was achieved with a relative standard deviation of less than 1.7%. The relative standard deviation of five TLDs

  1. Design and Manufacturing of Extremely Low Mass Flight Systems

    NASA Technical Reports Server (NTRS)

    Johnson, Michael R.

    2002-01-01

    Extremely small flight systems pose some unusual design and manufacturing challenges. The small size of the components that make up the system generally must be built with extremely tight tolerances to maintain the functionality of the assembled item. Additionally, the total mass of the system is extremely sensitive to what would be considered small perturbations in a larger flight system. The MUSES C mission, designed, built, and operated by Japan, has a small rover provided by NASA that falls into this small flight system category. This NASA-provided rover is used as a case study of an extremely small flight system design. The issues that were encountered with the rover portion of the MUSES C program are discussed and conclusions about the recommended mass margins at different stages of a small flight system project are presented.

  2. Extreme events in excitable systems and mechanisms of their generation.

    PubMed

    Ansmann, Gerrit; Karnatak, Rajat; Lehnertz, Klaus; Feudel, Ulrike

    2013-11-01

    We study deterministic systems, composed of excitable units of FitzHugh-Nagumo type, that are capable of self-generating and self-terminating strong deviations from their regular dynamics without the influence of noise or parameter change. These deviations are rare, short-lasting, and recurrent and can therefore be regarded as extreme events. Employing a range of methods we analyze dynamical properties of the systems, identifying features in the systems' dynamics that may qualify as precursors to extreme events. We investigate these features and elucidate mechanisms that may be responsible for the generation of the extreme events.

  3. A dynamical systems approach to studying midlatitude weather extremes

    NASA Astrophysics Data System (ADS)

    Messori, Gabriele; Caballero, Rodrigo; Faranda, Davide

    2017-04-01

    Extreme weather occurrences carry enormous social and economic costs and routinely garner widespread scientific and media coverage. The ability to predict these events is therefore a topic of crucial importance. Here we propose a novel predictability pathway for extreme events, by building upon recent advances in dynamical systems theory. We show that simple dynamical systems metrics can be used to identify sets of large-scale atmospheric flow patterns with similar spatial structure and temporal evolution on time scales of several days to a week. In regions where these patterns favor extreme weather, they afford a particularly good predictability of the extremes. We specifically test this technique on the atmospheric circulation in the North Atlantic region, where it provides predictability of large-scale wintertime surface temperature extremes in Europe up to 1 week in advance.

  4. Overview of the North America Climate Extremes Monitoring (NACEM) System

    NASA Astrophysics Data System (ADS)

    Lawrimore, J. H.; Heim, R. R.

    2007-05-01

    The IPCC Fourth Assessment Report and other climate assessments have documented an increasing trend in temperature and precipitation extremes, including hot days and nights, heavy precipitation events, and area affected by droughts. Extreme weather and climate events such as these often result in significant socioeconomic and environmental costs within affected areas. This reality along with the likelihood that trends toward more frequent and intense extreme events will increase in a warming world has focused attention on programs that can provide information to decision makers responsible for planning, response, and mitigation activities. Several government and university institutions throughout the U.S., Canada, and Mexico have partnered to improve monitoring of extremes across the North American Continent. This effort began in late 2002 with establishment of the North America Drought Monitor (NADM), an operational program for monitoring continent-scale drought conditions on an ongoing basis. Following the NADM, this trilateral partnership initiated development of a web- based climate extremes system to expand the capacity to monitor a wider range of climate extremes. Using daily data from stations across these three countries, the North American Climate Extremes Monitoring (NACEM) system now provides decision makers with the ability to monitor and analyze climate extremes on the continent. The U.S. and Canada are also collaborating in the creation of a near-real time operational component to monitor the occurrence of new daily, monthly, and all-time records for temperature, precipitation, and snowfall as they occur. Parallel development of a North American gridded database of daily temperature and precipitation supports these activities and will soon provide for the analysis of extremes on a regional, country, and continental-scale basis. This presentation will include an overview of the NACEM system and its products, the supporting database, observed changes in

  5. OSLD energy response performance and dose accuracy at 24 - 1250 keV: Comparison with TLD-100H and TLD-100

    SciTech Connect

    Kadir, A. B. A.; Priharti, W.; Samat, S. B.; Dolah, M. T.

    2013-11-27

    OSLD was evaluated in terms of energy response and accuracy of the measured dose in comparison with TLD-100H and TLD-100. The OSLD showed a better energy response performance for H{sub p}(10) whereas for H{sub p}(0.07), TLD-100H is superior than the others. The OSLD dose accuracy is comparable with the other two dosimeters since it fulfilled the requirement of the ICRP trumpet graph analysis.

  6. Power system extreme event screening using graphpartitioning

    SciTech Connect

    Lesieutre, Bernard C.; Roy, Sandip; Donde, Vaibhav; Pinar, Ali

    2006-09-06

    We propose a partitioning problem in a power system contextthat weighs the two objectives of minimizing cuts between partitions andmaximizing the power imbalance between partitions. We then pose theproblem in a purely graph theoretic sense. We offer an approximatesolution through relaxation of the integer problem and suggest refinementusing stochastic methods. Results are presented for the IEEE 30-bus and118-bus electric power systems.

  7. Preliminary Studies of Thermoluminescence Dosimeter (TLD) CaSO4:Dy Synthesis

    NASA Astrophysics Data System (ADS)

    Nuraeni, N.; Iskandar, F.; Waris, A.; Haryanto, F.

    2017-07-01

    Thermoluminescence dosimeter (TLD) CaSO4:Dy was synthesised by coprecipitation. The TLD was observed after radiation exposure to Strontium-90. The thermoluminescence intensity was read using a TLD Reader Harshaw 3500. The thermoluminescent response obtained was 59.29 nC. Then re-annealing was conducted with the temperature varied at 700, 800 and 900 °C. The thermoluminescent intensity obtained at temperatures of 700 °C, 800 °C and 900 °C was 66.12 nC, 169.45 nC, and 552.37 nC respectively. The sensitivity of the TLD increased in response to the re-annealing temperature rise. In addition to observing the thermoluminescence properties, a comparison was made between the TLD obtained from this experiment with an existing TLD in the market. Finally, also the glow-curve characteristics of the TLD were observed.

  8. Error Analysis of non-TLD HDR Brachytherapy Dosimetric Techniques

    NASA Astrophysics Data System (ADS)

    Amoush, Ahmad

    The American Association of Physicists in Medicine Task Group Report43 (AAPM-TG43) and its updated version TG-43U1 rely on the LiF TLD detector to determine the experimental absolute dose rate for brachytherapy. The recommended uncertainty estimates associated with TLD experimental dosimetry include 5% for statistical errors (Type A) and 7% for systematic errors (Type B). TG-43U1 protocol does not include recommendation for other experimental dosimetric techniques to calculate the absolute dose for brachytherapy. This research used two independent experimental methods and Monte Carlo simulations to investigate and analyze uncertainties and errors associated with absolute dosimetry of HDR brachytherapy for a Tandem applicator. An A16 MicroChamber* and one dose MOSFET detectors† were selected to meet the TG-43U1 recommendations for experimental dosimetry. Statistical and systematic uncertainty analyses associated with each experimental technique were analyzed quantitatively using MCNPX 2.6‡ to evaluate source positional error, Tandem positional error, the source spectrum, phantom size effect, reproducibility, temperature and pressure effects, volume averaging, stem and wall effects, and Tandem effect. Absolute dose calculations for clinical use are based on Treatment Planning System (TPS) with no corrections for the above uncertainties. Absolute dose and uncertainties along the transverse plane were predicted for the A16 microchamber. The generated overall uncertainties are 22%, 17%, 15%, 15%, 16%, 17%, and 19% at 1cm, 2cm, 3cm, 4cm, and 5cm, respectively. Predicting the dose beyond 5cm is complicated due to low signal-to-noise ratio, cable effect, and stem effect for the A16 microchamber. Since dose beyond 5cm adds no clinical information, it has been ignored in this study. The absolute dose was predicted for the MOSFET detector from 1cm to 7cm along the transverse plane. The generated overall uncertainties are 23%, 11%, 8%, 7%, 7%, 9%, and 8% at 1cm, 2cm, 3cm

  9. Spectrometer system for diffuse extreme ultraviolet radiation

    NASA Technical Reports Server (NTRS)

    Labov, Simon E.

    1989-01-01

    A unique grazing incidence spectrometer system has been designed to study diffuse line emission between 80 and 650 A with 10-30 A resolution. The minimum detectable emission line strength during a 5-min observation ranges from 100-2000 ph/sq cm sec str. The instrument uses mechanically ruled reflection gratings placed in front of a linear array of mirrors. These mirrors focus the spectral image on microchannel plate detectors located behind thin filters. The field of view is 40 min of arc by 15 deg, and there is no spatial imaging. This instrument has been fabricated, calibrated, and successfully flown on a sounding rocket to observe the astronomical background radiation.

  10. Weather in an extremely nearby substellar system

    NASA Astrophysics Data System (ADS)

    Buenzli, Esther; Marley, Mark; Apai, Daniel; Biller, Beth; Crossfield, Ian; Radigan, Jacqueline

    2015-12-01

    At a distance of only 2 pc, the brown dwarf binary WISE J104915.57-531906.1, also known as Luhman 16AB, is the third closest system from the Sun. As the closest substellar objects outside of the solar system, their unusual brightness makes these brown dwarfs of late-L and early-T spectral type a unique laboratory for the study of ultracool atmospheres. Their effective temperatures are very similar to those of directly imaged planets such as the HR8799 planets, and they share many atmospheric properties. Without a bright host star, the brown dwarf atmospheres can be studied in much greater detail. In particular, time-resolved spectroscopic observations have recently started to be used to provide new insights into heterogeneities in the cloud structure of brown dwarfs. Luhman 16B was the first brown dwarf to be mapped with Doppler Imaging, which resulted in a surface map with darker and brighter spots that may relate to different cloud features. We have now obtained spectroscopic time series with HST/WFC3 that allow us to measure the absolute flux changes over a broad wavelength range (0.8 - 1.7 microns) and cover several molecular and atomic absorption features, including for the first time the FeH feature that has been thought to be a good tracer of cloud holes. Because we detect significant variability in both Luhman 16A and B, effectively observing weather on these nearby worlds, we can for the first time directly characterize and compare the heterogeneous cloud structure in a co-eval L/T transition binary. The observations provide important insight into how clouds evolve and disappear across the L/T transition at ~1200 K, and the results are also very relevant for the interpretation of spectra of young directly imaged giant planets.

  11. Physics Characterization of TLD-600 and TLD-700 and Acceptance Testing of New XRAD 160 Biological X-Ray Irradiator

    NASA Astrophysics Data System (ADS)

    Cao, Yanan

    Project 1: Physics characterization of TLD-600 and TLD-700. Purpose: It is suggested that a pair of TLD-600 and TLD-700 can measure the exposure in neutron-photon mix fields. But the basic information of physics characterization of TLD-600 and 700 are not available. The purpose of this study was study the individual TLD variation and the energy dependence of TLD-600 and TLD-700. Methods: The individual calibration factors for 52 TLD-600 chips and 51 TLD-700 chips were determined under x-ray beams of 60 kVp, 80 kVp, 120 kVp, a mono-energetic 662 keV gamma beam of a Cs-137 source, and an Am-Be neutron beam (4.4 MeV). The individual calibration factor was calculated as the ratio of the group average response in uC/mR and the individual response in uC/mR. In addition, energy corrections factors for the individual calibration factors were determined, from each of the x-ray beams (60 kVp, 80 kVp, 120 kVp) to the 662 keV Cs-137 gamma beams. Results: For TLD-600, the range and relative standard deviation of the individual calibration factors are: 60 kVp (0.94003-1.0927, 3.5369%), 80 kVp (0.9395-1.0867, 3.0952%), 120 kVp (0.83403-1.0796, 4.5732%), 662 keV (0.80465-1.1926, 9.2515% ), AmBe (0.91740-0.94905, 3.0882% ); and the energy corrections factors relative to the 662 keV Cs-137 beams are: 60 kVp (1.2223), 80 kVp (1.1013), 120 kVp (1.0299). For TLD-700 the range and relative standard deviation of the individual calibration factors are: 60 kVp (0.94351-1.0630, 2.6044%), 80 kVp (0.91690-1.0614, 2.6996%), 120 kVp (0.95697-1.0474, 2.3606%), 662 keV (0.91348-1.2270, 4.2243%), AmBe (0.79330-1.2268, 9.1577%); and the energy corrections factors relative to the 662 keV Cs-137 beams are: 60 kVp (1.0373), 80 kVp (0.97661), 120 kVp (0.88532). Conclusion: We have measured individual calibration factors and the average energy correction factors for photon beams and Am-Be neutron beams. Our results will be used in the future experiments and measurements with TLD-600 and TLD-700. Project

  12. Experimental determination of the photon-energy dependent dose-to-water response of TLD600 and TLD700 (LiF:Mg,Ti) thermoluminescence detectors.

    PubMed

    Schwahofer, Andrea; Feist, Harald; Georg, Holger; Häring, Peter; Schlegel, Wolfgang

    2017-03-01

    The aim of this study has been the experimental determination of the energy dependent dose-to-water response of TLD600 and TLD700 thermoluminescent detectors (Harshaw) in X-ray beams with mean photon energies from about 20 to 200keV in comparison with (60)Co gamma rays and 6MV X-rays. Experiments were carried out in collaboration with the German secondary standard laboratory PTW Freiburg. The energy dependent relative responses of TLD600 and TLD700 thermoluminescence detectors were determined at radiation qualities between 30kVp and 280kVp. The overall uncertainty of the measured values was characterized by standard deviations varying from 1.2 to 3%. The present results agree with previous studies on the energy dependent dose-to-water response of TLD100. As an application example, the results were used to measure doses associated with X-ray imaging in image-guided radiotherapy.

  13. AN EXTREMELY CARBON-RICH, EXTREMELY METAL-POOR STAR IN THE SEGUE 1 SYSTEM

    SciTech Connect

    Norris, John E.; Yong, David; Gilmore, Gerard; Wyse, Rosemary F. G.; Frebel, Anna

    2010-10-10

    We report the analysis of high-resolution, high signal-to-noise ratio, spectra of an extremely metal-poor, extremely C-rich red giant, Seg 1-7, in Segue 1-described in the literature alternatively as an unusually extended globular cluster or an ultra-faint dwarf galaxy. The radial velocity of Seg 1-7 coincides precisely with the systemic velocity of Segue 1, and its chemical abundance signature of [Fe/H] = -3.52, [C/Fe] = +2.3, [N/Fe] = +0.8, [Na/Fe] = +0.53, [Mg/Fe] = +0.94, [Al/Fe] = +0.23, and [Ba/Fe] < -1.0 is similar to that of the rare and enigmatic class of Galactic halo objects designated CEMP-no (carbon-rich, extremely metal-poor with no enhancement (over solar ratios) of heavy neutron-capture elements). This is the first star in a Milky Way 'satellite' that unambiguously lies on the metal-poor, C-rich branch of the Aoki et al. bimodal distribution of field halo stars in the ([C/Fe], [Fe/H])-plane. Available data permit us only to identify Seg 1-7 as a member of an ultra-faint dwarf galaxy or as debris from the Sgr dwarf spheroidal galaxy. In either case, this demonstrates that at extremely low abundance, [Fe/H ] <-3.0, star formation and associated chemical evolution proceeded similarly in the progenitors of both the field halo and satellite systems. By extension, this is consistent with other recent suggestions that the most metal-poor dwarf spheroidal and ultra-faint dwarf satellites were the building blocks of the Galaxy's outer halo.

  14. Neutron dose measurements of Varian and Elekta linacs by TLD600 and TLD700 dosimeters and comparison with MCNP calculations

    PubMed Central

    Nedaie, Hassan Ali; Darestani, Hoda; Banaee, Nooshin; Shagholi, Negin; Mohammadi, Kheirollah; Shahvar, Arjang; Bayat, Esmaeel

    2014-01-01

    High-energy linacs produce secondary particles such as neutrons (photoneutron production). The neutrons have the important role during treatment with high energy photons in terms of protection and dose escalation. In this work, neutron dose equivalents of 18 MV Varian and Elekta accelerators are measured by thermoluminescent dosimeter (TLD) 600 and TLD700 detectors and compared with the Monte Carlo calculations. For neutron and photon dose discrimination, first TLDs were calibrated separately by gamma and neutron doses. Gamma calibration was carried out in two procedures; by standard 60Co source and by 18 MV linac photon beam. For neutron calibration by 241Am-Be source, irradiations were performed in several different time intervals. The Varian and Elekta linac heads and the phantom were simulated by the MCNPX code (v. 2.5). Neutron dose equivalent was calculated in the central axis, on the phantom surface and depths of 1, 2, 3.3, 4, 5, and 6 cm. The maximum photoneutron dose equivalents which calculated by the MCNPX code were 7.06 and 2.37 mSv.Gy-1 for Varian and Elekta accelerators, respectively, in comparison with 50 and 44 mSv.Gy-1 achieved by TLDs. All the results showed more photoneutron production in Varian accelerator compared to Elekta. According to the results, it seems that TLD600 and TLD700 pairs are not suitable dosimeters for neutron dosimetry inside the linac field due to high photon flux, while MCNPX code is an appropriate alternative for studying photoneutron production. PMID:24600167

  15. Neutron dose measurements of Varian and Elekta linacs by TLD600 and TLD700 dosimeters and comparison with MCNP calculations.

    PubMed

    Nedaie, Hassan Ali; Darestani, Hoda; Banaee, Nooshin; Shagholi, Negin; Mohammadi, Kheirollah; Shahvar, Arjang; Bayat, Esmaeel

    2014-01-01

    High-energy linacs produce secondary particles such as neutrons (photoneutron production). The neutrons have the important role during treatment with high energy photons in terms of protection and dose escalation. In this work, neutron dose equivalents of 18 MV Varian and Elekta accelerators are measured by thermoluminescent dosimeter (TLD) 600 and TLD700 detectors and compared with the Monte Carlo calculations. For neutron and photon dose discrimination, first TLDs were calibrated separately by gamma and neutron doses. Gamma calibration was carried out in two procedures; by standard 60Co source and by 18 MV linac photon beam. For neutron calibration by (241)Am-Be source, irradiations were performed in several different time intervals. The Varian and Elekta linac heads and the phantom were simulated by the MCNPX code (v. 2.5). Neutron dose equivalent was calculated in the central axis, on the phantom surface and depths of 1, 2, 3.3, 4, 5, and 6 cm. The maximum photoneutron dose equivalents which calculated by the MCNPX code were 7.06 and 2.37 mSv.Gy(-1) for Varian and Elekta accelerators, respectively, in comparison with 50 and 44 mSv.Gy(-1) achieved by TLDs. All the results showed more photoneutron production in Varian accelerator compared to Elekta. According to the results, it seems that TLD600 and TLD700 pairs are not suitable dosimeters for neutron dosimetry inside the linac field due to high photon flux, while MCNPX code is an appropriate alternative for studying photoneutron production.

  16. Robust neighboring extremal guidance for the advanced launch system

    NASA Astrophysics Data System (ADS)

    Bain, John; Speyer, Jason L.

    With the availability of modern flight computers, realtime neighboring extremal guidance seems feasible. To overcome sensitivity to unknown system parameters and environmental uncertainties, a robust neighboring extremal guidance scheme is proposed. About the optimal trajectory, the accessory problem in the calculus of variations is formed, generating a quadratic cost criterion in the perturbed states and controls. By formulating a disturbance attenuation problem based upon the second variation cost criterion, a differential game is formulated. The game theoretic cost criterion is minimized with respect to the perturbed control but maximized with respect to the unknown parameters in the linearized dynamics. The resulting differential game problem gives rise to a two-point boundary-value problem solved using the sweep method. The sweep method solution provides a linear robust neighboring extremal guidance scheme that is applied to the Advanced Launch System.

  17. Robust neighboring extremal guidance for the advanced launch system

    NASA Technical Reports Server (NTRS)

    Bain, John; Speyer, Jason L.

    1993-01-01

    With the availability of modern flight computers, realtime neighboring extremal guidance seems feasible. To overcome sensitivity to unknown system parameters and environmental uncertainties, a robust neighboring extremal guidance scheme is proposed. About the optimal trajectory, the accessory problem in the calculus of variations is formed, generating a quadratic cost criterion in the perturbed states and controls. By formulating a disturbance attenuation problem based upon the second variation cost criterion, a differential game is formulated. The game theoretic cost criterion is minimized with respect to the perturbed control but maximized with respect to the unknown parameters in the linearized dynamics. The resulting differential game problem gives rise to a two-point boundary-value problem solved using the sweep method. The sweep method solution provides a linear robust neighboring extremal guidance scheme that is applied to the Advanced Launch System.

  18. Robust neighboring extremal guidance for the advanced launch system

    NASA Technical Reports Server (NTRS)

    Bain, John; Speyer, Jason L.

    1993-01-01

    With the availability of modern flight computers, realtime neighboring extremal guidance seems feasible. To overcome sensitivity to unknown system parameters and environmental uncertainties, a robust neighboring extremal guidance scheme is proposed. About the optimal trajectory, the accessory problem in the calculus of variations is formed, generating a quadratic cost criterion in the perturbed states and controls. By formulating a disturbance attenuation problem based upon the second variation cost criterion, a differential game is formulated. The game theoretic cost criterion is minimized with respect to the perturbed control but maximized with respect to the unknown parameters in the linearized dynamics. The resulting differential game problem gives rise to a two-point boundary-value problem solved using the sweep method. The sweep method solution provides a linear robust neighboring extremal guidance scheme that is applied to the Advanced Launch System.

  19. A scheme for designing extreme multistable discrete dynamical systems

    NASA Astrophysics Data System (ADS)

    Chakraborty, Priyanka

    2017-09-01

    In this paper, we propose a scheme for designing discrete extreme multistable systems coupling two identical dynamical systems. Existence of infinitely many attractors in the system is obtained via partial synchronization between two systems for a given set of parameters. We give a conjecture that extreme multistable systems can be designed by coupling two m-dimensional dynamical systems in such a way that i (1 ≤ i≤ m-1) number of state variables of the two systems synchronize completely and (m-i) number of state variables keep constant difference. We demonstrate the applicability of our scheme in two-dimensional (2D) as well as three-dimensional (3D) discrete dynamical systems. In particular, we discuss our scheme taking coupled 2D Hénon maps, coupled 2D Duffing maps and coupled 3D Hénon maps. We have analytically shown the existence of fixed points and period-2 orbits in the coupled system with the variation of initial conditions. These analytically derived conditions matched very well with the numerical simulation results. Variation of the largest Lyapunov exponent with the initial conditions is shown to confirm the existence of extreme multistability in the model. Our scheme may be useful for designing physically, chemically and biologically useful multistable discrete dynamical systems.

  20. Extreme Space: Engaging and Educating the Public by Showcasing the Extremes of our Solar System

    NASA Astrophysics Data System (ADS)

    Lopes, R. M.; Davis, P. W.; Lowes, L. L.

    2003-12-01

    The period of 2003 to 2006 is an exciting time in solar system exploration, with a fleet of more than a dozen spacecraft exploring the extremes of our solar neighborhood. NASA's Solar System Exploration Education and Public Outreach Forum plans to mine the richness of this intense mission activity and related natural astronomical events to develop a cohesive story of exploration. This is a unique opportunity to raise awareness of our solar system and provide inspiration for student career choices. The concentration of events includes mission launches and endings, spacecraft flybys, encounters, and landings, and sample returns to Earth. The missions target an exciting variety of extreme destinations in the solar system including the Sun, comets, Mercury, Venus, Mars, Jupiter, Saturn, and Pluto. To weave the variety of activities together into a simple concept, the SSE E/PO community has selected Extreme Space as the basis of our unifying theme. Also referenced in the SSE Roadmap, this thread emphasizes the harsh environments of the planets and bodies, and the challenges of designing and executing robotic missions to explore them. The theme encompasses planetary missions, research, and astrobiology, and is logically extensible to the Sun, the Earth and comparisons to other planets, including extrasolar worlds. We plan audience-focused activities around this theme, aimed at the informal and K-12 formal education communities. We are providing one-stop access to SSE mission content and E/PO resources, and professional development opportunities for scientists, teachers and informal education professionals. Content and resource needs include a calendar of events, news alerts, a summary PowerPoint presentation, image and video collections, and thematic education package.

  1. Extreme Space: Engaging and Educating the Public by Showcasing the Extremes of Our Solar System

    NASA Astrophysics Data System (ADS)

    Davis, P. W.

    2003-05-01

    The period of 2003 to 2006 is a critical time in solar system exploration with a fleet of more than a dozen spacecraft exploring the extremes of our solar neighborhood. The Solar System Exploration Education and Public Outreach Forum plans to mine the richness of this intense mission activity and related natural astronomical events to develop a cohesive story of exploration. This is a unique opportunity to raise NASA visibility and provide an inspiration for student career choices. The concentration of events includes mission launches and endings, flybys, encounters, and landings, and sample returns to Earth, to an exciting variety of extreme destinations in the solar system including the Sun, comets, Mercury, Venus, Mars, Jupiter, Saturn, and Pluto. To weave the variety of activities together into a simple concept, the SSE E/PO community has selected Extreme Space as the basis of our unifying theme. Also referenced in the SSE Roadmap, this thread emphasizes the harsh environments of the planets and bodies, and the needs for and challenges of designing and executing robotic missions to explore them. Since venturing beyond the Earth to other worlds is unique in the world of space exploration, this can serve as an additional audience hook. It encompasses SSE missions, research, and astrobiology, and is logically extensible to the Sun, the Earth and comparisons to other planets, including extrasolar worlds. We plan audience-focused activities around this theme, aimed at the informal and K-12 formal education communities. We are providing one-stop access to SSE mission content and E/PO resources, and professional development opportunities for scientists, teachers and informal education professionals. Content and resource needs include a calendar of events, news alerts, a summary PowerPoint presentation, image and video collections, and thematic education package.

  2. Response of Simple, Model Systems to Extreme Conditions

    SciTech Connect

    Ewing, Rodney C.; Lang, Maik

    2015-07-30

    The focus of the research was on the application of high-pressure/high-temperature techniques, together with intense energetic ion beams, to the study of the behavior of simple oxide systems (e.g., SiO2, GeO2, CeO2, TiO2, HfO2, SnO2, ZnO and ZrO2) under extreme conditions. These simple stoichiometries provide unique model systems for the analysis of structural responses to pressure up to and above 1 Mbar, temperatures of up to several thousands of kelvin, and the extreme energy density generated by energetic heavy ions (tens of keV/atom). The investigations included systematic studies of radiation- and pressure-induced amorphization of high P-T polymorphs. By studying the response of simple stoichiometries that have multiple structural “outcomes”, we have established the basic knowledge required for the prediction of the response of more complex structures to extreme conditions. We especially focused on the amorphous state and characterized the different non-crystalline structure-types that result from the interplay of radiation and pressure. For such experiments, we made use of recent technological developments, such as the perforated diamond-anvil cell and in situ investigation using synchrotron x-ray sources. We have been particularly interested in using extreme pressures to alter the electronic structure of a solid prior to irradiation. We expected that the effects of modified band structure would be evident in the track structure and morphology, information which is much needed to describe theoretically the fundamental physics of track-formation. Finally, we investigated the behavior of different simple-oxide, composite nanomaterials (e.g., uncoated nanoparticles vs. core/shell systems) under coupled, extreme conditions. This provided insight into surface and boundary effects on phase stability under extreme conditions.

  3. Terrestrial Applications of Extreme Environment Stirling Space Power Systems

    NASA Technical Reports Server (NTRS)

    Dyson, Rodger. W.

    2012-01-01

    NASA has been developing power systems capable of long-term operation in extreme environments such as the surface of Venus. This technology can use any external heat source to efficiently provide electrical power and cooling; and it is designed to be extremely efficient and reliable for extended space missions. Terrestrial applications include: use in electric hybrid vehicles; distributed home co-generation/cooling; and quiet recreational vehicle power generation. This technology can reduce environmental emissions, petroleum consumption, and noise while eliminating maintenance and environmental damage from automotive fluids such as oil lubricants and air conditioning coolant. This report will provide an overview of this new technology and its applications.

  4. Extreme value statistics for dynamical systems with noise

    NASA Astrophysics Data System (ADS)

    Faranda, Davide; Milhazes Freitas, Jorge; Lucarini, Valerio; Turchetti, Giorgio; Vaienti, Sandro

    2013-09-01

    We study the distribution of maxima (extreme value statistics) for sequences of observables computed along orbits generated by random transformations. The underlying, deterministic, dynamical system can be regular or chaotic. In the former case, we show that, by perturbing rational or irrational rotations with additive noise, an extreme value law appears, regardless of the intensity of the noise, while unperturbed rotations do not admit such limiting distributions. In the case of deterministic chaotic dynamics, we will consider observables specially designed to study the recurrence properties in the neighbourhood of periodic points. Hence, the exponential limiting law for the distribution of maxima is modified by the presence of the extremal index, a positive parameter not larger than one, whose inverse gives the average size of the clusters of extreme events. The theory predicts that such a parameter is unitary when the system is perturbed randomly. We perform sophisticated numerical tests to assess how strong the impact of noise level is when finite time series are considered. We find agreement with the asymptotic theoretical results but also non-trivial behaviour in the finite range. In particular, our results suggest that, in many applications where finite datasets can be produced or analysed, one must be careful in assuming that the smoothing nature of noise prevails over the underlying deterministic dynamics.

  5. Extreme value laws in dynamical systems under physical observables

    NASA Astrophysics Data System (ADS)

    Holland, Mark P.; Vitolo, Renato; Rabassa, Pau; Sterk, Alef E.; Broer, Henk W.

    2012-03-01

    Extreme value theory for chaotic deterministic dynamical systems is a rapidly expanding area of research. Given a system and a real function (observable) defined on its phase space, extreme value theory studies the limit probabilistic laws obeyed by large values attained by the observable along orbits of the system. Based on this theory, the so-called block maximum method is often used in applications for statistical prediction of large value occurrences. In this method, one performs statistical inference for the parameters of the Generalised Extreme Value (GEV) distribution, using maxima over blocks of regularly sampled observable values along an orbit of the system. The observables studied so far in the theory are expressed as functions of the distance with respect to a point, which is assumed to be a density point of the system’s invariant measure. However, at least with respect to the ambient (usually Euclidean) metric, this is not the structure of the observables typically encountered in physical applications, such as windspeed or vorticity in atmospheric models. In this paper we consider extreme value limit laws for observables which are not expressed as functions of the distance (in the ambient metric) from a density point of the dynamical system. In such cases, the limit laws are no longer determined by the functional form of the observable and the dimension of the invariant measure: they also depend on the specific geometry of the underlying attractor and of the observable’s level sets. We present a collection of analytical and numerical results, starting with a toral hyperbolic automorphism as a simple template to illustrate the main ideas. We then formulate our main results for a uniformly hyperbolic system, the solenoid map. We also discuss non-uniformly hyperbolic examples of maps (Hénon and Lozi maps) and of flows (the Lorenz63 and Lorenz84 models). Our purpose is to outline the main ideas and to highlight several serious problems found in the

  6. TLD assessment of mouse dosimetry during microCT imaging

    PubMed Central

    Figueroa, Said Daibes; Winkelmann, Christopher T.; Miller, William H.; Volkert, Wynn A.; Hoffman, Timothy J.

    2008-01-01

    Advances in laboratory animal imaging have provided new resources for noninvasive biomedical research. Among these technologies is microcomputed tomography (microCT) which is widely used to obtain high resolution anatomic images of small animals. Because microCT utilizes ionizing radiation for image formation, radiation exposure during imaging is a concern. The objective of this study was to quantify the radiation dose delivered during a standard microCT scan. Radiation dose was measured using thermoluminescent dosimeters (TLDs), which were irradiated employing an 80 kVp x-ray source, with 0.5 mm Al filtration and a total of 54 mA s for a full 360 deg rotation of the unit. The TLD data were validated using a 3.2 cm3 CT ion chamber probe. TLD results showed a single microCT scan air kerma of 78.0±5.0 mGy when using a poly(methylmethacrylate) (PMMA) anesthesia support module and an air kerma of 92.0±6.0 mGy without the use of the anesthesia module. The validation CT ion chamber study provided a measured radiation air kerma of 81.0±4.0 mGy and 97.0±5.0 mGy with and without the PMMA anesthesia module, respectively. Internal TLD analysis demonstrated an average mouse organ radiation absorbed dose of 76.0±5.0 mGy. The author’s results have defined x-ray exposure for a routine microCT study which must be taken into consideration when performing serial molecular imaging studies involving the microCT imaging modality. PMID:18841837

  7. TLD assessment of mouse dosimetry during microCT imaging

    SciTech Connect

    Figueroa, Said Daibes; Winkelmann, Christopher T.; Miller, William H.; Volkert, Wynn A.; Hoffman, Timothy J.

    2008-09-15

    Advances in laboratory animal imaging have provided new resources for noninvasive biomedical research. Among these technologies is microcomputed tomography (microCT) which is widely used to obtain high resolution anatomic images of small animals. Because microCT utilizes ionizing radiation for image formation, radiation exposure during imaging is a concern. The objective of this study was to quantify the radiation dose delivered during a standard microCT scan. Radiation dose was measured using thermoluminescent dosimeters (TLDs), which were irradiated employing an 80 kVp x-ray source, with 0.5 mm Al filtration and a total of 54 mA s for a full 360 deg rotation of the unit. The TLD data were validated using a 3.2 cm{sup 3} CT ion chamber probe. TLD results showed a single microCT scan air kerma of 78.0{+-}5.0 mGy when using a poly(methylmethacrylate) (PMMA) anesthesia support module and an air kerma of 92.0{+-}6.0 mGy without the use of the anesthesia module. The validation CT ion chamber study provided a measured radiation air kerma of 81.0{+-}4.0 mGy and 97.0{+-}5.0 mGy with and without the PMMA anesthesia module, respectively. Internal TLD analysis demonstrated an average mouse organ radiation absorbed dose of 76.0{+-}5.0 mGy. The author's results have defined x-ray exposure for a routine microCT study which must be taken into consideration when performing serial molecular imaging studies involving the microCT imaging modality.

  8. Relative Efficiency Of TLD-100 Exposed to X-Rays

    SciTech Connect

    Ixquiac-Cabrera, J. M.; Gamboa-de Buen, I.; Avila, O.; Brandan, M. E.

    2008-08-11

    The relative efficiency of TLD-100 (LiF:Mg,Ti) exposed to X-rays in the range from 30 to 250 kV, with respect to {sup 60}CO gamma rays has been measured. Glow curves were deconvoluted into peaks 3 to 9. All efficiencies were greater than 1 having a maximum of 1.38 for the dosimetric region (peaks 3+4+5) and peaks 4, 5 and 9, and 2.2 for peaks 6a, 6b, 7 and 8 at the effective energy of 24 keV.

  9. Public Health System Response to Extreme Weather Events.

    PubMed

    Hunter, Mark D; Hunter, Jennifer C; Yang, Jane E; Crawley, Adam W; Aragón, Tomás J

    2016-01-01

    Extreme weather events, unpredictable and often far-reaching, constitute a persistent challenge for public health preparedness. The goal of this research is to inform public health systems improvement through examination of extreme weather events, comparing across cases to identify recurring patterns in event and response characteristics. Structured telephone-based interviews were conducted with representatives from health departments to assess characteristics of recent extreme weather events and agencies' responses. Response activities were assessed using the Centers for Disease Control and Prevention Public Health Emergency Preparedness Capabilities framework. Challenges that are typical of this response environment are reported. Forty-five local health departments in 20 US states. Respondents described public health system responses to 45 events involving tornadoes, flooding, wildfires, winter weather, hurricanes, and other storms. Events of similar scale were infrequent for a majority (62%) of the communities involved; disruption to critical infrastructure was universal. Public Health Emergency Preparedness Capabilities considered most essential involved environmental health investigations, mass care and sheltering, surveillance and epidemiology, information sharing, and public information and warning. Unanticipated response activities or operational constraints were common. We characterize extreme weather events as a "quadruple threat" because (1) direct threats to population health are accompanied by damage to public health protective and community infrastructure, (2) event characteristics often impose novel and pervasive burdens on communities, (3) responses rely on critical infrastructures whose failure both creates new burdens and diminishes response capacity, and (4) their infrequency and scale further compromise response capacity. Given the challenges associated with extreme weather events, we suggest opportunities for organizational learning and

  10. Extreme event statistics of daily rainfall: dynamical systems approach

    NASA Astrophysics Data System (ADS)

    Cigdem Yalcin, G.; Rabassa, Pau; Beck, Christian

    2016-04-01

    We analyse the probability densities of daily rainfall amounts at a variety of locations on Earth. The observed distributions of the amount of rainfall fit well to a q-exponential distribution with exponent q close to q≈ 1.3. We discuss possible reasons for the emergence of this power law. In contrast, the waiting time distribution between rainy days is observed to follow a near-exponential distribution. A careful investigation shows that a q-exponential with q≈ 1.05 yields the best fit of the data. A Poisson process where the rate fluctuates slightly in a superstatistical way is discussed as a possible model for this. We discuss the extreme value statistics for extreme daily rainfall, which can potentially lead to flooding. This is described by Fréchet distributions as the corresponding distributions of the amount of daily rainfall decay with a power law. Looking at extreme event statistics of waiting times between rainy days (leading to droughts for very long dry periods) we obtain from the observed near-exponential decay of waiting times extreme event statistics close to Gumbel distributions. We discuss superstatistical dynamical systems as simple models in this context.

  11. High numerical aperture projection system for extreme ultraviolet projection lithography

    DOEpatents

    Hudyma, Russell M.

    2000-01-01

    An optical system is described that is compatible with extreme ultraviolet radiation and comprises five reflective elements for projecting a mask image onto a substrate. The five optical elements are characterized in order from object to image as concave, convex, concave, convex, and concave mirrors. The optical system is particularly suited for ring field, step and scan lithography methods. The invention uses aspheric mirrors to minimize static distortion and balance the static distortion across the ring field width which effectively minimizes dynamic distortion. The present invention allows for higher device density because the optical system has improved resolution that results from the high numerical aperture, which is at least 0.14.

  12. Investigation of radiation doses in open space using TLD detectors.

    PubMed

    Reitz, G; Facius, R; Bilski, P; Olko, P

    2002-01-01

    The low energy component of the cosmic radiation field is strongly modified by the shielding of the spacecraft and it is time and location dependent. Thermoluminescent lithium fluoride detectors have been applied to determine the radiation doses inside the ESA-Facility BIOPAN. The BIOPAN facility was mounted outside and launched on a Foton spacecraft and opened to space to allow exposure of several experiments to open space. Standard TLD-600. TLD-700 chips, two layers MTS-Ns sintered pellets with different effective thickness of the sensitive layer and MTS-N of different thickness have been exposed with different shielding thicknesses in front of them. The measured TL signal in the 0.1 mm thick detector just shielded by an aluminised Kapton foil of 25 microm thickness in front yielded a dose of 29.8 Gy (calibrated with 137Cs gamma rays) for an exposure time of 12.7 days: after 2.5 g.cm(-2) shielding the doses dropped to 3 mGy. The monitoring of radiation doses and its depth dose distribution outside the spacecraft are of great interest for radiation protection of astronauts working in open space. The knowledge of depth-dose distribution is a prerequisite to determine the organ doses an astronaut will receive during an extravehicular activity (EVA). The BIOPAN experiments are to be continued in the future.

  13. Power laws of complex systems from extreme physical information.

    PubMed

    Frieden, B Roy; Gatenby, Robert A

    2005-09-01

    Many complex systems obey allometric, or power, laws y=Y x(a) . Here y > or = 0 is the measured value of some system attribute a , Y> or =0 is a constant, and x is a stochastic variable. Remarkably, for many living systems the exponent a is limited to values n/4 , n=0, +/-1, +/-2.... Here x is the mass of a randomly selected creature in the population. These quarter-power laws hold for many attributes, such as pulse rate (n=-1) . Allometry has, in the past, been theoretically justified on a case-by-case basis. An ultimate goal is to find a common cause for allometry of all types and for both living and nonliving systems. The principle I-J=extremum of extreme physical information is found to provide such a cause. It describes the flow of Fisher information J-->I from an attribute value a on the cell level to its exterior observation y . Data y are formed via a system channel function y identical to f (x,a) , with f (x,a) to be found. Extremizing the difference I-J through variation of f (x,a) results in a general allometric law f (x,a) identical to y=Y x(a) . Darwinian evolution is presumed to cause a second extremization of I-J , now with respect to the choice of a . The solution is a=n/4 , n=0,+/-1,+/-2..., defining the particular powers of biological allometry. Under special circumstances, the model predicts that such biological systems are controlled by only two distinct intracellular information sources. These sources are conjectured to be cellular DNA and cellular transmembrane ion gradients.

  14. Weather Climate Interactions and Extreme Events in the Climate System

    NASA Astrophysics Data System (ADS)

    Roundy, P. E.

    2015-12-01

    The most pronounced local impacts of climate change would occur in association with extreme weather events superimposed on the altered climate. Thus a major thrust of recent efforts in the climate community has been to assess how extreme regional events such as cold air outbreaks, heat waves, tropical cyclones, floods, droughts, and severe weather might change with the climate. Many of these types of events are poorly simulated in climate models because of insufficient spatial resolution and insufficient quality parameterization of sub grid scale convection and radiation processes. This talk summarizes examples selected from those discussed below of how weather and climate events can be interconnected so that the physics of natural climate and weather phenomena depend on each other, thereby complicating our ability to simulate extreme events. A major focus of the chapter is on the Madden Julian oscillation (MJO), which is associated with alternating eastward-moving planetary scale regions of enhanced and suppressed moist deep convection favoring warm pool regions in the tropics. The MJO modulates weather events around the world and influences the evolution of interannual climate variability. We first discuss how the MJO evolves together with the seasonal cycle, the El Niño/southern oscillation (ENSO), and the extratropical circulation, then continue with a case study illustration of how El Niño is intrinsically coupled to intraseasonal and synoptic weather events such as the MJO and westerly wind bursts. This interconnectedness in the system implies that modeling many types of regional extreme weather events requires more than simply downscaling coarse climate model signals to nested regional models because extreme outcomes in a region can depend on poorly simulated extreme weather in distant parts of the world. The authors hope that an improved understanding of these types of interactions between signals across scales of time and space will ultimately yield

  15. High latitude equivalent current systems during extremely quiet times

    NASA Technical Reports Server (NTRS)

    Rostoker, G.; Chen, A. J.; Yasuhara, F.; Akasofu, S.-I.; Kawasaki, K.

    1974-01-01

    The magnetic perturbation patterns in the polar cap and auroral zone regions are obtained for extremely quiet days using two different techniques. It is shown that the form of the equivalent current flow pattern is extremely sensitive to the level of quietness, and that even so-called quiet days are at times disturbed by substorm activity. Certain characteristic equivalent flow not typically observed during substorms is noted in the polar cap, and this flow appears to be associated with effects of polar cap perturbations discussed by Svalgaard (1973). A region of equatorward flow at high latitudes near the dawn meridian, appears to be Hall current driven by an eastward electric field. The dayside sub-auroral zone is dominated by the Sq-current system, while the nightside shows no significant current flow in the absence of substorm activity.

  16. Determination of photostimulation parameters and testing of high-dose PTTL method using TLD-500K detectors

    NASA Astrophysics Data System (ADS)

    Kazantseva, M. G.; Kortov, V. S.

    2016-09-01

    TLD-500K standard detectors sample were studied. The goal of this work is to evaluate the possibility of usage of phototransferred thermoluminescence of TLD-500K detectors for high-dose measurements. This work resulted in finding of the optimal conditions of photostimulation for irradiated TLD-500K detectors.

  17. A pyramid sensor based AO system for Extremely Large Telescopes

    NASA Astrophysics Data System (ADS)

    Quirós-Pacheco, F.; Pinna, E.; Esposito, S.; Riccardi, A.; Rabien, S.

    2011-09-01

    Since the introduction of the pyramid wavefront sensor in the mid 90s, various authors have shown both theoretically and with the aid of simulations that pyramid sensors can achieve a better performance than traditional Shack-Hartmann wavefront sensors. Recently the First-Light AO system (FLAO) at the Large Binocular Telescope has demonstrated excellent on sky performance achieved with a pyramid based system. Motivated by these results, we will present in this paper a first heuristic analysis scaling up the FLAO performance to the case of an Extremely Large Telescope (ELT). We support our arguments with preliminary numerical simulations for the case of the European ELT using the M4 adaptive corrector and a properly matched pyramid sensor. Such a system could be used as a first-light natural guide-star AO system for the European ELT offering the advantages of a demonstrated AO system with practically off-the-shelf technology.

  18. Characterization and Impact of Extreme Forecast Errors on Power Systems

    SciTech Connect

    Heydt, Gerald T.; Vittal, Vijay; Malhara, Sunita V.; Makarov, Yuri V.; Zhou, Ning; Etingov, Pavel V.

    2011-12-15

    Extreme events in the electrical power system, caused by the load and wind forecasting errors, can impact the power system infrastructure via two main avenues. The first avenue is a sudden and significant power unbalance exceeding reasonable operating reserve capacity. The second is a sudden increase of power flows on the system critical paths causing transmission violations. The challenge in managing these system unbalances is more significant for a standalone balancing area operation. The consolidation of balancing authorities into a single balancing area can offset the operating reserve problem but this strategy enhances incremental power flows on the transmission interfaces, potentially leading to more unpredictable transmission congestion. This paper evaluates the expectancy of occurrence of tail events due to forecast error extremes using California ISO and BPA data. Having this type of information, independent system operators and operating utilities could be better prepared to address the tail events by exploring alternative reserve options such as: wide area control coordination, new operating proce-dures and remedial actions.

  19. Hydroclimatic Extremes: Inferences and Prediction from a Dynamical Systems Perspective

    NASA Astrophysics Data System (ADS)

    Lall, U.

    2015-12-01

    Hydroclimatic extremes , such as major floods and droughts, or periods with a high frequency of clustered tornadoes, fires or cyclones, have often been thought of as random, rare events, and much of the literature on these topics has been obsessed with the estimation of the tail probabilities (e.g., the 100 year event) of these processes. It has taken the "acceptance" of the notion of climate change to question whether the machinery developed for such estimation or even the associated questions are reasonable. However, much of the literature that has evolved since has focused on how to detect and model changes in these probabilities using a variety of methods. In this talk, I will argue that while such efforts may be useful in a certain, outdated context, they are not necessarily leading to an improvement in eihter the science of the application of the science to disaster risk mitigation. I develop an argument that hydroclimatic extremes result from an organization of the associated global and local dynamical systems that leads to the systems trajectories locking into a particular region of state space. Such excursions could be considered as rare events, in their ultimate expression, or in their frequency of visitation and persistence in those states. An open question is whether the dynamics of the system under such conditions are marked by high or low predictabilty in the Lyapunov sense. A characterization of the dimension and predictability of hydroclimatic extremes would allow us to better understand the potential implications of climate change, and also of whether or not a regional drought or similar persistent regime is likely to dissipate or grow.

  20. Wireless pilot monitoring system for extreme race conditions.

    PubMed

    Pino, Esteban J; Arias, Diego E; Aqueveque, Pablo; Melin, Pedro; Curtis, Dorothy W

    2012-01-01

    This paper presents the design and implementation of an assistive device to monitor car drivers under extreme conditions. In particular, this system is designed in preparation for the 2012 Atacama Solar Challenge to be held in the Chilean desert. Actual preliminary results show the feasibility of such a project including physiological and ambient sensors, real-time processing algorithms, wireless data transmission and a remote monitoring station. Implementation details and field results are shown along with a discussion of the main problems found in real-life telemetry monitoring.

  1. Neighboring extremal guidance for systems with a piecewise linear control

    NASA Technical Reports Server (NTRS)

    Hull, David G.; Helfrich, Clifford E.

    1991-01-01

    The neighboring extremal feedback control law is developed for systems with a piecewise linear control for the case where the optimal control is obtained by nonlinear programming techniques. To develop the control perturbation for a given deviation from the nominal path, the second variation is minimized subject to the constraint that the final conditions be satisfied. This process leads to a feedback relationship between the control perturbation and the measured deviation from the nominal state. A simple example, the lunar launch problem, is used to demonstrate the validity of the guidance law. For model errors on the order of 5 percent, the results indicate that 5 percent errors occur in the final conditions.

  2. Extreme nonlinear optics of two-level systems

    SciTech Connect

    Tritschler, T.; Muecke, O. D.; Wegener, M.

    2003-09-01

    For Rabi frequencies comparable to, or even larger than, the transition frequency of a two-level system, the regime of extreme nonlinear optics is reached. Here, we give an overview of the radiated light intensity as a function of carrier frequency of light, transition frequency, Rabi frequency, spectrometer frequency, as well as of the shape and duration of the exciting optical pulses. The graphical representations reveal an amazing complexity and beauty of the nonlinear optical response. Analytical results within the ''square-wave approximation'' qualitatively reproduce many of the intricate features of the exact numerical calculations.

  3. Reducing Waste in Extreme Scale Systems through Introspective Analysis

    SciTech Connect

    Bautista-Gomez, Leonardo; Gainaru, Ana; Perarnau, Swann; Tiwari, Devesh; Gupta, Saurabh; Engelmann, Christian; Cappello, Franck; Snir, Marc

    2016-01-01

    Resilience is an important challenge for extreme- scale supercomputers. Today, failures in supercomputers are assumed to be uniformly distributed in time. However, recent studies show that failures in high-performance computing systems are partially correlated in time, generating periods of higher failure density. Our study of the failure logs of multiple supercomputers show that periods of higher failure density occur with up to three times more than the average. We design a monitoring system that listens to hardware events and forwards important events to the runtime to detect those regime changes. We implement a runtime capable of receiving notifications and adapt dynamically. In addition, we build an analytical model to predict the gains that such dynamic approach could achieve. We demonstrate that in some systems, our approach can reduce the wasted time by over 30%.

  4. High order test bench for extreme adaptive optics system optimization

    NASA Astrophysics Data System (ADS)

    Aller-Carpentier, Emmanuel; Kasper, Markus; Martinez, Patrice; Vernet, Elise; Fedrigo, Enrico; Soenke, Christian; Tordo, Sébastien; Hubin, Norbert; Verinaud, Christophe; Esposito, Simone; Pinna, Enrico; Puglisi, Alfio; Tozzi, Andrea; Quiros, Fernando; Basden, Alastair G.; Goodsell, Stephen J.; Love, Gordon D.; Myers, Richard M.

    2008-07-01

    High-contrast imagers dedicated to the search for extrasolar planets are currently being developed for the VLT (SPHERE) and Gemini (GPI) observatories. A vital part of such a high-contrast imager is the extreme adaptive optics (XAO) system that very efficiently removes effects of atmospheric turbulence and instrument aberrations. The high order test bench (HOT) implements an XAO system under realistic telescope conditions reproduced by star and turbulence generators. New technological developments (32x32 actuator micro deformable mirror, read-noise free electron multiplying CCD60, SPARTA real time computer) are used to study and compare two potential XAO wave front sensors: The Pyramid- and the Shack-Hartmann wave front sensors. We will describe the overall design of HOT including the sub-systems. We will present the closed loop study results of the behavior of the Shack-Hartmann wave front sensor in terms of linearity, sensitivity to calibration errors, performance and other specific issues.

  5. Assessing mid-latitude dynamics in extreme event attribution systems

    NASA Astrophysics Data System (ADS)

    Mitchell, Daniel; Davini, Paolo; Harvey, Ben; Massey, Neil; Haustein, Karsten; Woollings, Tim; Jones, Richard; Otto, Fredi; Guillod, Benoit; Sparrow, Sarah; Wallom, David; Allen, Myles

    2017-06-01

    Atmospheric modes of variability relevant for extreme temperature and precipitation events are evaluated in models currently being used for extreme event attribution. A 100 member initial condition ensemble of the global circulation model HadAM3P is compared with both the multi-model ensemble from the Coupled Model Inter-comparison Project, Phase 5 (CMIP5) and the CMIP5 atmosphere-only counterparts (AMIP5). The use of HadAM3P allows for huge ensembles to be computed relatively fast, thereby providing unique insights into the dynamics of extremes. The analysis focuses on mid Northern Latitudes (primarily Europe) during winter, and is compared with ERA-Interim reanalysis. The tri-modal Atlantic eddy-driven jet distribution is remarkably well captured in HadAM3P, but not so in the CMIP5 or AMIP5 multi-model mean, although individual models fare better. The well known underestimation of blocking in the Atlantic region is apparent in CMIP5 and AMIP5, and also, to a lesser extent, in HadAM3P. Pacific blocking features are well produced in all modeling initiatives. Blocking duration is biased towards models reproducing too many short-lived events in all three modelling systems. Associated storm tracks are too zonal over the Atlantic in the CMIP5 and AMIP5 ensembles, but better simulated in HadAM3P with the exception of being too weak over Western Europe. In all cases, the CMIP5 and AMIP5 performances were almost identical, suggesting that the biases in atmospheric modes considered here are not strongly coupled to SSTs, and perhaps other model characteristics such as resolution are more important. For event attribution studies, it is recommended that rather than taking statistics over the entire CMIP5 or AMIP5 available models, only models capable of producing the relevant dynamical phenomena be employed.

  6. Seismic Vibration Control of Elevated Water Tank by TLD and Validation of Full-Scale TLD Model through Real-Time-Hybrid-Testing

    NASA Astrophysics Data System (ADS)

    Roy, A.; Staino, A.; (D Ghosh, A.; Basu, B.; Chatterjee, S.

    2016-09-01

    Elevated water tanks (EWTs), being top-heavy structures, are highly vulnerable to earthquake forces, and several have experienced damage/failure in past seismic events. However, as these are critical facilities whose continued performance in the post-earthquake scenario is of vital concern, it is significant to investigate their seismic vibration control using reliable and cost-effective passive dampers such as the Tuned Liquid Damper (TLD). Here, this aspect is studied for flexible EWT structures, such as those with annular shaft supports. The criterion of tuning the sloshing frequency of the TLD to the structural frequency necessitates dimensions of the TLD larger than those hitherto examined in literature. Hence the nonlinear model of the TLD based on established shallow water wave theory is verified for large container size by employing Real-Time-Hybrid-Testing (RTHT). Simulation studies are further carried out on a realistic example of a flexible EWT structure with TLDs. Results indicate that the TLD can be applied very effectively for the seismic vibration mitigation of EWTs.

  7. Methane Leaks from Natural Gas Systems Follow Extreme Distributions.

    PubMed

    Brandt, Adam R; Heath, Garvin A; Cooley, Daniel

    2016-11-15

    Future energy systems may rely on natural gas as a low-cost fuel to support variable renewable power. However, leaking natural gas causes climate damage because methane (CH4) has a high global warming potential. In this study, we use extreme-value theory to explore the distribution of natural gas leak sizes. By analyzing ∼15 000 measurements from 18 prior studies, we show that all available natural gas leakage data sets are statistically heavy-tailed, and that gas leaks are more extremely distributed than other natural and social phenomena. A unifying result is that the largest 5% of leaks typically contribute over 50% of the total leakage volume. While prior studies used log-normal model distributions, we show that log-normal functions poorly represent tail behavior. Our results suggest that published uncertainty ranges of CH4 emissions are too narrow, and that larger sample sizes are required in future studies to achieve targeted confidence intervals. Additionally, we find that cross-study aggregation of data sets to increase sample size is not recommended due to apparent deviation between sampled populations. Understanding the nature of leak distributions can improve emission estimates, better illustrate their uncertainty, allow prioritization of source categories, and improve sampling design. Also, these data can be used for more effective design of leak detection technologies.

  8. Methane Leaks from Natural Gas Systems Follow Extreme Distributions

    SciTech Connect

    Brandt, Adam R.; Heath, Garvin A.; Cooley, Daniel

    2016-10-14

    Future energy systems may rely on natural gas as a low-cost fuel to support variable renewable power. However, leaking natural gas causes climate damage because methane (CH4) has a high global warming potential. In this study, we use extreme-value theory to explore the distribution of natural gas leak sizes. By analyzing ~15,000 measurements from 18 prior studies, we show that all available natural gas leakage datasets are statistically heavy-tailed, and that gas leaks are more extremely distributed than other natural and social phenomena. A unifying result is that the largest 5% of leaks typically contribute over 50% of the total leakage volume. While prior studies used lognormal model distributions, we show that lognormal functions poorly represent tail behavior. Our results suggest that published uncertainty ranges of CH4 emissions are too narrow, and that larger sample sizes are required in future studies to achieve targeted confidence intervals. Additionally, we find that cross-study aggregation of datasets to increase sample size is not recommended due to apparent deviation between sampled populations. Finally, understanding the nature of leak distributions can improve emission estimates, better illustrate their uncertainty, allow prioritization of source categories, and improve sampling design. Also, these data can be used for more effective design of leak detection technologies.

  9. Methane Leaks from Natural Gas Systems Follow Extreme Distributions

    DOE PAGES

    Brandt, Adam R.; Heath, Garvin A.; Cooley, Daniel

    2016-10-14

    Future energy systems may rely on natural gas as a low-cost fuel to support variable renewable power. However, leaking natural gas causes climate damage because methane (CH4) has a high global warming potential. In this study, we use extreme-value theory to explore the distribution of natural gas leak sizes. By analyzing ~15,000 measurements from 18 prior studies, we show that all available natural gas leakage datasets are statistically heavy-tailed, and that gas leaks are more extremely distributed than other natural and social phenomena. A unifying result is that the largest 5% of leaks typically contribute over 50% of the totalmore » leakage volume. While prior studies used lognormal model distributions, we show that lognormal functions poorly represent tail behavior. Our results suggest that published uncertainty ranges of CH4 emissions are too narrow, and that larger sample sizes are required in future studies to achieve targeted confidence intervals. Additionally, we find that cross-study aggregation of datasets to increase sample size is not recommended due to apparent deviation between sampled populations. Finally, understanding the nature of leak distributions can improve emission estimates, better illustrate their uncertainty, allow prioritization of source categories, and improve sampling design. Also, these data can be used for more effective design of leak detection technologies.« less

  10. Predictability of extremes in non-linear hierarchically organized systems

    NASA Astrophysics Data System (ADS)

    Kossobokov, V. G.; Soloviev, A.

    2011-12-01

    Understanding the complexity of non-linear dynamics of hierarchically organized systems progresses to new approaches in assessing hazard and risk of the extreme catastrophic events. In particular, a series of interrelated step-by-step studies of seismic process along with its non-stationary though self-organized behaviors, has led already to reproducible intermediate-term middle-range earthquake forecast/prediction technique that has passed control in forward real-time applications during the last two decades. The observed seismic dynamics prior to and after many mega, great, major, and strong earthquakes demonstrate common features of predictability and diverse behavior in course durable phase transitions in complex hierarchical non-linear system of blocks-and-faults of the Earth lithosphere. The confirmed fractal nature of earthquakes and their distribution in space and time implies that many traditional estimations of seismic hazard (from term-less to short-term ones) are usually based on erroneous assumptions of easy tractable analytical models, which leads to widespread practice of their deceptive application. The consequences of underestimation of seismic hazard propagate non-linearly into inflicted underestimation of risk and, eventually, into unexpected societal losses due to earthquakes and associated phenomena (i.e., collapse of buildings, landslides, tsunamis, liquefaction, etc.). The studies aimed at forecast/prediction of extreme events (interpreted as critical transitions) in geophysical and socio-economical systems include: (i) large earthquakes in geophysical systems of the lithosphere blocks-and-faults, (ii) starts and ends of economic recessions, (iii) episodes of a sharp increase in the unemployment rate, (iv) surge of the homicides in socio-economic systems. These studies are based on a heuristic search of phenomena preceding critical transitions and application of methodologies of pattern recognition of infrequent events. Any study of rare

  11. Four-mirror extreme ultraviolet (EUV) lithography projection system

    DOEpatents

    Cohen, Simon J; Jeong, Hwan J; Shafer, David R

    2000-01-01

    The invention is directed to a four-mirror catoptric projection system for extreme ultraviolet (EUV) lithography to transfer a pattern from a reflective reticle to a wafer substrate. In order along the light path followed by light from the reticle to the wafer substrate, the system includes a dominantly hyperbolic convex mirror, a dominantly elliptical concave mirror, spherical convex mirror, and spherical concave mirror. The reticle and wafer substrate are positioned along the system's optical axis on opposite sides of the mirrors. The hyperbolic and elliptical mirrors are positioned on the same side of the system's optical axis as the reticle, and are relatively large in diameter as they are positioned on the high magnification side of the system. The hyperbolic and elliptical mirrors are relatively far off the optical axis and hence they have significant aspherical components in their curvatures. The convex spherical mirror is positioned on the optical axis, and has a substantially or perfectly spherical shape. The spherical concave mirror is positioned substantially on the opposite side of the optical axis from the hyperbolic and elliptical mirrors. Because it is positioned off-axis to a degree, the spherical concave mirror has some asphericity to counter aberrations. The spherical concave mirror forms a relatively large, uniform field on the wafer substrate. The mirrors can be tilted or decentered slightly to achieve further increase in the field size.

  12. A millisecond pulsar in an extremely wide binary system

    NASA Astrophysics Data System (ADS)

    Bassa, C. G.; Janssen, G. H.; Stappers, B. W.; Tauris, T. M.; Wevers, T.; Jonker, P. G.; Lentati, L.; Verbiest, J. P. W.; Desvignes, G.; Graikou, E.; Guillemot, L.; Freire, P. C. C.; Lazarus, P.; Caballero, R. N.; Champion, D. J.; Cognard, I.; Jessner, A.; Jordan, C.; Karuppusamy, R.; Kramer, M.; Lazaridis, K.; Lee, K. J.; Liu, K.; Lyne, A. G.; McKee, J.; Osłowski, S.; Perrodin, D.; Sanidas, S.; Shaifullah, G.; Smits, R.; Theureau, G.; Tiburzi, C.; Zhu, W. W.

    2016-08-01

    We report on 22 yr of radio timing observations of the millisecond pulsar J1024-0719 by the telescopes participating in the European Pulsar Timing Array (EPTA). These observations reveal a significant second derivative of the pulsar spin frequency and confirm the discrepancy between the parallax and Shklovskii distances that has been reported earlier. We also present optical astrometry, photometry and spectroscopy of 2MASS J10243869-0719190. We find that it is a low-metallicity main-sequence star (K7V spectral type, [M/H] = -1.0, Teff = 4050 ± 50 K) and that its position, proper motion and distance are consistent with those of PSR J1024-0719. We conclude that PSR J1024-0719 and 2MASS J10243869-0719190 form a common proper motion pair and are gravitationally bound. The gravitational interaction between the main-sequence star and the pulsar accounts for the spin frequency derivatives, which in turn resolves the distance discrepancy. Our observations suggest that the pulsar and main-sequence star are in an extremely wide (Pb > 200 yr) orbit. Combining the radial velocity of the companion and proper motion of the pulsar, we find that the binary system has a high spatial velocity of 384 ± 45 km s-1 with respect to the local standard of rest and has a Galactic orbit consistent with halo objects. Since the observed main-sequence companion star cannot have recycled the pulsar to millisecond spin periods, an exotic formation scenario is required. We demonstrate that this extremely wide-orbit binary could have evolved from a triple system that underwent an asymmetric supernova explosion, though find that significant fine-tuning during the explosion is required. Finally, we discuss the implications of the long period orbit on the timing stability of PSR J1024-0719 in light of its inclusion in pulsar timing arrays.

  13. A new detection system for extremely small vertically mounted cantilevers.

    PubMed

    Antognozzi, M; Ulcinas, A; Picco, L; Simpson, S H; Heard, P J; Szczelkun, M D; Brenner, B; Miles, M J

    2008-09-24

    Detection techniques currently used in scanning force microscopy impose limitations on the geometrical dimensions of the probes and, as a consequence, on their force sensitivity and temporal response. A new technique, based on scattered evanescent electromagnetic waves (SEW), is presented here that can detect the displacement of the extreme end of a vertically mounted cantilever. The resolution of this method is tested using different cantilever sizes and a theoretical model is developed to maximize the detection sensitivity. The applications presented here clearly show that the SEW detection system enables the use of force sensors with sub-micron size, opening new possibilities in the investigation of biomolecular systems and high speed imaging. Two types of cantilevers were successfully tested: a high force sensitivity lever with a spring constant of 0.17 pN nm(-1) and a resonant frequency of 32 kHz; and a high speed lever with a spring constant of 50 pN nm(-1) and a resonant frequency of 1.8 MHz. Both these force sensors were fabricated by modifying commercial microcantilevers in a focused ion beam system. It is important to emphasize that these modified cantilevers could not be detected by the conventional optical detection system used in commercial atomic force microscopes.

  14. Advanced Life Systems for Extreme Environments: An Arctic Application

    NASA Technical Reports Server (NTRS)

    Lewis, Carol E.; Stanford, Kerry L.; Bubenheim, David L.; Covington, Alan (Technical Monitor)

    1995-01-01

    The problems of obtaining adequate pure drinking water and disposing of liquid and solid waste in the U.S. Arctic, a region where virtually all water is frozen solid for much of the year, has led to unsanitary solutions (U.S. Arctic Research Commission). These solutions are also damaging to the environment. Sanitation and a safe water supply are particularly problems in rural villages. About one-fourth of Alaska's 86.000 Native residents live in these communities. They are without running water and use plastic buckets for toilets. The outbreak of diseases is believed to be partially attributable to exposure to human waste. Villages with the most frequent outbreaks of disease are those in which running water is difficult to obtain (Office of Technology Assessment, 1994). Waste is emptied into open lagoons, rivers, or onto the sea coast. It does not degrade rapidly and in addition to affecting human health, can be harmful to the fragile ecology of the Arctic and the indigenous wildlife and fish populations. Advanced Life Systems for Extreme Environments (ALSEE) provides a solution to sanitation and safe water problems. The system uses an advanced integrated technology developed for Antarctic and space applications. ALSEE uses the systems approach to address more than waste and water problems. By incorporating hydroponic horticulture and aquaculture into the waste treatment system, ALSEE addresses the quality and quantity of fresh foods available to Arctic residents. A temperate climate is required for year-round plant growth. ALSEE facilities can be designed to include a climate controlled area within the structure. This type of environment is a change from the long periods of darkness and cold found in the Arctic and can help alleviate stress so often associated with these extremes. While the overall concept of ALSEE projects is advanced, system facilities can be operated by village residents with appropriate training. ALSEE provides continuing training and

  15. Advanced Life Systems for Extreme Environments: An Arctic Application

    NASA Technical Reports Server (NTRS)

    Lewis, Carol E.; Stanford, Kerry L.; Bubenheim, David L.; Covington, Alan (Technical Monitor)

    1995-01-01

    The problems of obtaining adequate pure drinking water and disposing of liquid and solid waste in the U.S. Arctic, a region where virtually all water is frozen solid for much of the year, has led to unsanitary solutions (U.S. Arctic Research Commission). These solutions are also damaging to the environment. Sanitation and a safe water supply are particularly problems in rural villages. About one-fourth of Alaska's 86.000 Native residents live in these communities. They are without running water and use plastic buckets for toilets. The outbreak of diseases is believed to be partially attributable to exposure to human waste. Villages with the most frequent outbreaks of disease are those in which running water is difficult to obtain (Office of Technology Assessment, 1994). Waste is emptied into open lagoons, rivers, or onto the sea coast. It does not degrade rapidly and in addition to affecting human health, can be harmful to the fragile ecology of the Arctic and the indigenous wildlife and fish populations. Advanced Life Systems for Extreme Environments (ALSEE) provides a solution to sanitation and safe water problems. The system uses an advanced integrated technology developed for Antarctic and space applications. ALSEE uses the systems approach to address more than waste and water problems. By incorporating hydroponic horticulture and aquaculture into the waste treatment system, ALSEE addresses the quality and quantity of fresh foods available to Arctic residents. A temperate climate is required for year-round plant growth. ALSEE facilities can be designed to include a climate controlled area within the structure. This type of environment is a change from the long periods of darkness and cold found in the Arctic and can help alleviate stress so often associated with these extremes. While the overall concept of ALSEE projects is advanced, system facilities can be operated by village residents with appropriate training. ALSEE provides continuing training and

  16. Extreme oxygen isotope ratios in the early Solar System.

    PubMed

    Aléon, Jérôme; Robert, François; Duprat, Jean; Derenne, Sylvie

    2005-09-15

    The origins of the building blocks of the Solar System can be studied using the isotopic composition of early planetary and meteoritic material. Oxygen isotopes in planetary materials show variations at the per cent level that are not related to the mass of the isotopes; rather, they result from the mixture of components having different nucleosynthetic or chemical origins. Isotopic variations reaching orders of magnitude in minute meteoritic grains are usually attributed to stellar nucleosynthesis before the birth of the Solar System, whereby different grains were contributed by different stars. Here we report the discovery of abundant silica-rich grains embedded in meteoritic organic matter, having the most extreme 18O/16O and 17O/16O ratios observed (both approximately 10(-1)) together with a solar silicon isotopic composition. Both O and Si isotopes indicate a single nucleosynthetic process. These compositions can be accounted for by one of two processes: a single exotic evolved star seeding the young Solar System, or irradiation of the circumsolar gas by high energy particles accelerated during an active phase of the young Sun. We favour the latter interpretation, because the observed compositions are usually not expected from nucleosynthetic processes in evolved stars, whereas they are predicted by the selective trapping of irradiation products.

  17. Water Detected in the Terrestrial Zone of Extreme Solar Systems

    NASA Astrophysics Data System (ADS)

    Farihi, Jay

    2015-12-01

    Life as we know it requires water in contact with a rocky planetary surface. In the Solar System, water and other volatiles must have been delivered to a dry Earth from planetesimals, where asteroids in the outer main belt and Jupiter-Saturn region are excellent candidates. The first extrasolar analog of these rocky and water-rich planetesimals was reported between ESS II and III (Farihi et al. 2013, Science, 342, 218), and there is now evidence for additional examples. These results imply an underlying population of large, extrasolar planetesimals formed near a snow line, and suggesting a common mechanism for water delivery to habitable exoplanets.I will present Hubble, Spitzer, and ground-based data that demonstrate the confirmed and likely water-rich nature of exo-asteroids identified in a growing number of white dwarf planetary systems. These extreme solar systems formed and evolved around A-type (and similar) stars -- now firmly retired -- and the asteroid debris now orbits and pollutes the white dwarf with heavy elements, including oxygen in excess of that expected for oxide minerals. The abundance patterns are also carbon-poor, indicating the parent bodies were not icy planetesimals analogous to comets, but instead similar in overall composition to asteroids in the outer main belt.Importantly, these remnant exoplanetary systems imply architectures similar to the Solar System, where a giant planet exterior to a snow line perturbs rocky asteroids on the interior. Thus, they appear to share basic characteristics with HR 8799, Vega, Fomalhaut, and epsilon Eridani where two disks of debris are separated by giant planet(s), with one belt near the snow line. If such archictectures are as common as implied by polluted white dwarfs, then at least 30% of 1.2-3.0 Msun stars have both the tools and ingredentients for water delivery in their terrestrial planet zones.

  18. An operations and command systems for the extreme ultraviolet explorer

    NASA Technical Reports Server (NTRS)

    Muscettola, Nicola; Korsmeyer, David J.; Olson, Eric C.; Wong, Gary

    1994-01-01

    About 40% of the budget of a scientific spacecraft mission is usually consumed by Mission Operations & Data Analysis (MO&DA) with MO driving these costs. In the current practice, MO is separated from spacecraft design and comes in focus relatively late in the mission life cycle. As a result, spacecraft may be designed that are very difficult to operate. NASA centers have extensive MO expertise but often lessons learned in one mission are not exploited for other parallel or future missions. A significant reduction of MO costs is essential to ensure a continuing and growing access to space for the scientific community. We are addressing some of these issues with a highly automated payload operations and command system for an existing mission, the Extreme Ultraviolet Explorer (EUVE). EUVE is currently operated jointly by the Goddard Space Flight Center (GSFC), responsible for spacecraft operations, and the Center for Extreme Ultraviolet Astrophysics (CEA) of the University of California, Berkeley, which controls the telescopes and scientific instruments aboard the satellite. The new automated system is being developed by a team including personnel from the NASA Ames Research Center (ARC), the Jet Propulsion Laboratory (JPL) and the Center for EUV Astrophysics (CEA). An important goal of the project is to provide AI-based technology that can be easily operated by nonspecialists in AI. Another important goal is the reusability of the techniques for other missions. Models of the EUVE spacecraft need to be built both for planning/scheduling and for monitoring. In both cases, our modeling tools allow the assembly of a spacecraft model from separate sub-models of the various spacecraft subsystems. These sub-models are reusable; therefore, building mission operations systems for another small satellite mission will require choosing pre-existing modules, reparametrizing them with respect to the actual satellite telemetry information, and reassembling them in a new model. We

  19. Electro-Mechanical Systems for Extreme Space Environments

    NASA Technical Reports Server (NTRS)

    Mojarradi, Mohammad M.; Tyler, Tony R.; Abel, Phillip B.; Levanas, Greg

    2011-01-01

    Exploration beyond low earth orbit presents challenges for hardware that must operate in extreme environments. The current state of the art is to isolate and provide heating for sensitive hardware in order to survive. However, this protection results in penalties of weight and power for the spacecraft. This is particularly true for electro-mechanical based technology such as electronics, actuators and sensors. Especially when considering distributed electronics, many electro-mechanical systems need to be located in appendage type locations, making it much harder to protect from the extreme environments. The purpose of this paper to describe the advances made in the area of developing electro-mechanical technology to survive these environments with minimal protection. The Jet Propulsion Lab (JPL), the Glenn Research Center (GRC), the Langley Research Center (LaRC), and Aeroflex, Inc. over the last few years have worked to develop and test electro-mechanical hardware that will meet the stringent environmental demands of the moon, and which can also be leveraged for other challenging space exploration missions. Prototype actuators and electronics have been built and tested. Brushless DC actuators designed by Aeroflex, Inc have been tested with interface temperatures as low as 14 degrees Kelvin. Testing of the Aeroflex design has shown that a brushless DC motor with a single stage planetary gearbox can operate in low temperature environments for at least 120 million cycles (measured at motor) if long life is considered as part of the design. A motor control distributed electronics concept developed by JPL was built and operated at temperatures as low as -160 C, with many components still operational down to -245 C. Testing identified the components not capable of meeting the low temperature goal of -230 C. This distributed controller is universal in design with the ability to control different types of motors and read many different types of sensors. The controller

  20. Optical Design for Extremely Large Telescope Adaptive Optics Systems

    SciTech Connect

    Bauman, Brian J.

    2003-01-01

    Designing an adaptive optics (AO) system for extremely large telescopes (ELT's) will present new optical engineering challenges. Several of these challenges are addressed in this work, including first-order design of multi-conjugate adaptive optics (MCAO) systems, pyramid wavefront sensors (PWFS's), and laser guide star (LGS) spot elongation. MCAO systems need to be designed in consideration of various constraints, including deformable mirror size and correction height. The y,{bar y} method of first-order optical design is a graphical technique that uses a plot with marginal and chief ray heights as coordinates; the optical system is represented as a segmented line. This method is shown to be a powerful tool in designing MCAO systems. From these analyses, important conclusions about configurations are derived. PWFS's, which offer an alternative to Shack-Hartmann (SH) wavefront sensors (WFS's), are envisioned as the workhorse of layer-oriented adaptive optics. Current approaches use a 4-faceted glass pyramid to create a WFS analogous to a quad-cell SH WFS. PWFS's and SH WFS's are compared and some newly-considered similarities and PWFS advantages are presented. Techniques to extend PWFS's are offered: First, PWFS's can be extended to more pixels in the image by tiling pyramids contiguously. Second, pyramids, which are difficult to manufacture, can be replaced by less expensive lenslet arrays. An approach is outlined to convert existing SH WFS's to PWFS's for easy evaluation of PWFS's. Also, a demonstration of PWFS's in sensing varying amounts of an aberration is presented. For ELT's, the finite altitude and finite thickness of LGS's means that the LGS will appear elongated from the viewpoint of subapertures not directly under the telescope. Two techniques for dealing with LGS spot elongation in SH WFS's are presented. One method assumes that the laser will be pulsed and uses a segmented micro-electromechanical system (MEMS) to track the LGS light subaperture by

  1. Comparison of dosimeter response: ionization chamber, TLD, and Gafchromic EBT2 film in 3D-CRT, IMRT, and SBRT techniques for lung cancer

    NASA Astrophysics Data System (ADS)

    Fitriandini, A.; Wibowo, W. E.; Pawiro, S. A.

    2016-03-01

    This research was conducted by measuring point dose in the target area (lungs), heart, and spine using four dosimeters (PTW N30013, Exradin A16, TLD, and the Gafchromic EBT2 film). The measurement was performed in CIRS 002LFC thorax phantom. The main objective of this study was to compare the dosimetry of those different systems. Dose measurements performed only in a single fraction of irradiation. The measurements result shown that TLD has the least accuracy and precision. As the effect of volume averaging, ionization chamber reaches the discrepancy value up to -13.30% in the target area. EBT2 film has discrepancy value of <1% in the 3D-CRT and IMRT techniques. This dosimeter is proposed to be an appropriate alternative dosimeter to be used at point dose verification.

  2. Extreme accumulation of nucleotides in simulated hydrothermal pore systems

    PubMed Central

    Baaske, Philipp; Weinert, Franz M.; Duhr, Stefan; Lemke, Kono H.; Russell, Michael J.; Braun, Dieter

    2007-01-01

    We simulate molecular transport in elongated hydrothermal pore systems influenced by a thermal gradient. We find extreme accumulation of molecules in a wide variety of plugged pores. The mechanism is able to provide highly concentrated single nucleotides, suitable for operations of an RNA world at the origin of life. It is driven solely by the thermal gradient across a pore. On the one hand, the fluid is shuttled by thermal convection along the pore, whereas on the other hand, the molecules drift across the pore, driven by thermodiffusion. As a result, millimeter-sized pores accumulate even single nucleotides more than 108-fold into micrometer-sized regions. The enhanced concentration of molecules is found in the bulk water near the closed bottom end of the pore. Because the accumulation depends exponentially on the pore length and temperature difference, it is considerably robust with respect to changes in the cleft geometry and the molecular dimensions. Whereas thin pores can concentrate only long polynucleotides, thicker pores accumulate short and long polynucleotides equally well and allow various molecular compositions. This setting also provides a temperature oscillation, shown previously to exponentially replicate DNA in the protein-assisted PCR. Our results indicate that, for life to evolve, complicated active membrane transport is not required for the initial steps. We find that interlinked mineral pores in a thermal gradient provide a compelling high-concentration starting point for the molecular evolution of life. PMID:17494767

  3. SU-E-I-09: Application of LiF:Mg,Cu (TLD-100H) Dosimeters for in Diagnostic Radiology

    SciTech Connect

    Sina, S; Zeinali, B; Karimipourfard, M; Lotfalizadeh, F; Sadeghi, M; Faghihi, R

    2014-06-01

    Purpose: Accurate dosimetery is very essential in diagnostic radiology. The goal of this study is to verify the application of LiF:Mg,Cu,P (TLD100H) in obtaining the Entrance skin dose (ESD) of patients undergoing diagnostic radiology. The results of dosimetry performed by TLD-100H, were compared with those obtained by TLD100, which is a common dosimeter in diagnostic radiology. Methods: In this study the ESD values were measured using two types of Thermoluminescence dosimeters (TLD-100, and TLD-100H) for 16 patients undergoing diagnostic radiology (lumbar spine imaging). The ESD values were also obtained by putting the two types of TLDs at the surface of Rando phantom for different imaging techniques and different views (AP, and lateral). The TLD chips were annealed with a standard procedure, and the ECC values for each TLD was obtained by exposing the chips to equal amount of radiation. Each time three TLD chips were covered by thin dark plastic covers, and were put at the surface of the phantom or the patient. The average reading of the three chips was used for obtaining the dose. Results: The results show a close agreement between the dose measuered by the two dosimeters.According to the results of this study, the TLD-100H dosimeters have higher sensitivities (i.e.signal(nc)/dose) than TLD-100.The ESD values varied between 2.71 mGy and 26.29 mGy with the average of 11.89 mGy for TLD-100, and between 2.55 mGy and 27.41 mGy with the average of 12.32 mGy for measurements. Conclusion: The TLD-100H dosimeters are suggested as effective dosimeters for dosimetry in low dose fields because of their higher sensitivities.

  4. Response of TLD-100 in mixed fields of photons and electrons.

    PubMed

    Lawless, Michael J; Junell, Stephanie; Hammer, Cliff; DeWerd, Larry A

    2013-01-01

    Thermoluminescent dosimeters (TLDs) are routinely used for dosimetric measurements of high energy photon and electron fields. However, TLD response in combined fields of photon and electron beam qualities has not been characterized. This work investigates the response of TLD-100 (LiF:Mg,Ti) to sequential irradiation by high-energy photon and electron beam qualities. TLDs were irradiated to a known dose by a linear accelerator with a 6 MV photon beam, a 6 MeV electron beam, and a NIST-traceable (60)Co beam. TLDs were also irradiated in a mixed field of the 6 MeV electron beam and the 6 MV photon beam. The average TLD response per unit dose of the TLDs for each linac beam quality was normalized to the average response per unit dose of the TLDs irradiated by the (60)Co beam. Irradiations were performed in water and in a Virtual Water™ phantom. The 6 MV photon beam and 6 MeV electron beam were used to create dose calibration curves relating TLD response to absorbed dose to water, which were applied to the TLDs irradiated in the mixed field. TLD relative response per unit dose in the mixed field was less sensitive than the relative response in the photon field and more sensitive than the relative response in the electron field. Application of the photon dose calibration curve to the TLDs irradiated in a mixed field resulted in an underestimation of the delivered dose, while application of the electron dose calibration curve resulted in an overestimation of the dose. The relative response of TLD-100 in mixed fields fell between the relative response in the photon-only and electron-only fields. TLD-100 dosimetry of mixed fields must account for this intermediate response to minimize the estimation errors associated with calibration factors obtained from a single beam quality.

  5. A method to minimise the fading effects of LiF:Mg,Ti (TLD-600 and TLD-700) using a pre-heat technique.

    PubMed

    Lee, YoungJu; Won, Yuho; Kang, Kidoo

    2015-04-01

    Passive integrating dosemeters [thermoluminescent dosimeter (TLD) and optically stimulated luminescence (OSL)] are the only legally permitted individual dosemeters for occupational external radiation exposure monitoring in Korea. Also its maximum issuing cycle does not exceed 3 months, and the Korean regulations require personal dosemeters for official assessment of external radiation exposure to be issued by an approved or rather an accredited dosimetry service according to ISO/IEC 17025. KHNP (Korea Hydro & Nuclear Power, LTD), a unique operating company of nuclear power plants (NPPs) in Korea, currently has a plan to extend a TLD issuing cycle from 1 to 3 months under the authors' fading error criteria, ±10%. The authors have performed a feasibility study that minimises post-irradiation fading effects within their maximum reading cycle employing pre-heating technique. They repeatedly performed irradiation/reading a bare TLD chip to determine optimum pre-heating conditions by analysing each glow curve. The optimum reading conditions within the maximum reading cycle of 3 months were decided: a pre-heating temperature of 165°C, a pre-heating time of 9 s, a heating rate of 25°C s(-1), a reading temperature of 300°C and an acquisition time of 10 s. The fading result of TLD-600 and TLD-700 carried by newly developed time temperature profile (TTP) showed a much smaller fading effect than that of current TTP. The result showed that the fading error due to a developed TTP resulted in a ∼5% signal loss, whereas a current TTP caused a ∼15% loss. The authors also carried out a legal performance test on newly developed TTP to confirm its possibility as an official dosemeter. The legal performance tests that applied the developed TTP satisfied the criteria for all the test categories.

  6. Evaluating secondary neutron doses of a refined shielded design for a medical cyclotron using the TLD approach

    NASA Astrophysics Data System (ADS)

    Lin, Jye-Bin; Tseng, Hsien-Chun; Liu, Wen-Shan; Lin, Ding-Bang; Hsieh, Teng-San; Chen, Chien-Yi

    2013-11-01

    An increasing number of cyclotrons at medical centers in Taiwan have been installed to generate radiopharmaceutical products. An operating cyclotron generates immense amounts of secondary neutrons from reactions such the 18O(p, n)18F, used in the production of FDG. This intense radiation can be hazardous to public health, particularly to medical personnel. To increase the yield of 18F-FDG from 4200 GBq in 2005 to 48,600 GBq in 2011, Chung Shan Medical University Hospital (CSMUH) has prolonged irradiation time without changing the target or target current to meet requirements regarding the production 18F. The CSMUH has redesigned the CTI Radioisotope Delivery System shield. The lack of data for a possible secondary neutron doses has increased due to newly designed cyclotron rooms. This work aims to evaluate secondary neutron doses at a CTI cyclotron center using a thermoluminescent dosimeter (TLD-600). Two-dimensional neutron doses were mapped and indicated that neutron doses were high as neutrons leaked through self-shielded blocks and through the L-shaped concrete shield in vault rooms. These neutron doses varied markedly among locations close to the H218O target. The Monte Carlo simulation and minimum detectable dose are also discussed and demonstrated the reliability of using the TLD-600 approach. Findings can be adopted by medical centers to identify radioactive hot spots and develop radiation protection.

  7. The Colors of Extreme Outer Solar System Objects

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott S.

    2010-04-01

    Extreme outer solar system objects have possible origins beyond the Kuiper Belt edge, high inclinations, very large semimajor axes, or large perihelion distances. Thirty-three such objects were observed in this work to determine their optical colors. All three objects that have been dynamically linked to the inner Oort Cloud by various authors ((90377) Sedna, 2006 SQ372, and (87269) 2000 OO67) were found to have ultra-red surface material (spectral gradient, S ~ 25). Ultra-red material is generally associated with rich organics and the low inclination "cold" classical Kuiper Belt objects (KBOs). The observations detailed here show that very red material may be a more general feature for objects kept far from the Sun. The recently discovered retrograde outer solar system objects (2008 KV42 and 2008 YB3) and the high inclination object (127546) 2002 XU93 show only moderately red surfaces (S ~ 9) very similar to known comets, suspected dead comets, Jupiter and Neptune Trojans, irregular satellites, D-type asteroids, and damocloids. The extended or detached disk objects, which have large perihelion distances and are thus considered to be detached from the influence of the giant planets but yet have large eccentricities, are found to have mostly moderately red colors (10 <~ S <~ 18). The colors of the detached disk objects, including the dynamically unusual 2004 XR190 and (148209) 2000 CR105, are similar to the scattered disk and Plutino populations. Thus the detached disk, scattered disk, Plutino, and high inclination "hot" classical objects likely have a similar mix of objects from the same source regions. Outer classical KBOs, including (48639) 1995 TL8, were found to have very red surfaces (18 <~ S <~ 30). The low inclination "cold" classical KBOs, outer classical KBOs and possibly the inner Oort Cloud appear to be dominated by ultra-red objects (S >~ 25) and thus do not likely have a similar mix of objects as the other outer solar system reservoirs such as the

  8. THE COLORS OF EXTREME OUTER SOLAR SYSTEM OBJECTS

    SciTech Connect

    Sheppard, Scott S.

    2010-04-15

    Extreme outer solar system objects have possible origins beyond the Kuiper Belt edge, high inclinations, very large semimajor axes, or large perihelion distances. Thirty-three such objects were observed in this work to determine their optical colors. All three objects that have been dynamically linked to the inner Oort Cloud by various authors ((90377) Sedna, 2006 SQ{sub 372}, and (87269) 2000 OO{sub 67}) were found to have ultra-red surface material (spectral gradient, S {approx} 25). Ultra-red material is generally associated with rich organics and the low inclination 'cold' classical Kuiper Belt objects (KBOs). The observations detailed here show that very red material may be a more general feature for objects kept far from the Sun. The recently discovered retrograde outer solar system objects (2008 KV{sub 42} and 2008 YB{sub 3}) and the high inclination object (127546) 2002 XU{sub 93} show only moderately red surfaces (S {approx} 9) very similar to known comets, suspected dead comets, Jupiter and Neptune Trojans, irregular satellites, D-type asteroids, and damocloids. The extended or detached disk objects, which have large perihelion distances and are thus considered to be detached from the influence of the giant planets but yet have large eccentricities, are found to have mostly moderately red colors (10 {approx}< S {approx}< 18). The colors of the detached disk objects, including the dynamically unusual 2004 XR{sub 190} and (148209) 2000 CR{sub 105}, are similar to the scattered disk and Plutino populations. Thus the detached disk, scattered disk, Plutino, and high inclination 'hot' classical objects likely have a similar mix of objects from the same source regions. Outer classical KBOs, including (48639) 1995 TL{sub 8}, were found to have very red surfaces (18 {approx}< S {approx}< 30). The low inclination 'cold' classical KBOs, outer classical KBOs and possibly the inner Oort Cloud appear to be dominated by ultra-red objects (S {approx}> 25) and thus do not

  9. SU-E-J-101: Retroactive Calculation of TLD and Film Dose in Anthropomorphic Phantom as Assessment of Updated TPS Performance

    SciTech Connect

    Alkhatib, H; Oves, S

    2014-06-01

    Purpose: To demonstrate a quick and comprehensive method verifying the accuracy of the updated dose model by recalculating dose distribution in an anthropomorphic phantom with a new version of the TPS and comparing the results to measured values. Methods: CT images and IMRT plan of an RPC anthropomorphic head phantom, previously calculated by Pinnacle 9.0, was re-computed using Pinnacle 9.2 and 9.6. The dosimeters within the phantom include four TLD capsules representing a primary PTV, two TLD capsules representing a secondary PTV, and two TLD capsules representing an organ at risk. Also included were three sheets of Gafchromic film. Performance of the updated TPS version was assessed by recalculating point doses and dose profiles corresponding to TLD and film position respectively and then comparing the results to reported values by the RPC. Results: Comparing calculated doses to reported measured doses from the RPC yielded an average disagreement of 1.48%, 2.04% and 2.10% for versions 9.0, 9.2, 9.6 respectively. Computed doses points all meet the RPC's passing criteria with the exception of the point representing the superior organ at risk in version 9.6. However, qualitative analysis of the recalculated dose profiles showed improved agreement with those of the RPC, especially in the penumbra region. Conclusion: This work has demonstrated the calculation results of Pinnacle 9.2 and 9.6 vs 9.0 version. Additionally, this study illustrates a method for the user to gain confidence upgrade to a newer version of the treatment planning system.

  10. On extremal quantum states of composite systems with fixed marginals

    NASA Astrophysics Data System (ADS)

    Rudolph, Oliver

    2004-11-01

    We study the convex set C(ρ1,ρ2) of all bipartite quantum states with fixed marginal states ρ1 and ρ2. The extremal states in this set have recently been characterized by Parthasarathy [Ann. Henri Poincaré (to appear), quant-ph/0307182]. Here we present an alternative necessary and sufficient condition for a state in C(ρ1,ρ2) to be extremal. Our approach is based on a canonical duality between bipartite states and a certain class of completely positive maps and has the advantage that it is easier to check and to construct explicit examples of extremal states. In dimension 2×2 we give a simple new proof for the fact that all extremal states in C(1/21,1/21) are precisely the projectors onto maximally entangled wave functions. We also prove that in higher dimension this does not hold and construct an explicit example of an extremal state in C(1/31,1/31) that is not maximally entangled. Generalizations of this result to higher dimensions are also discussed.

  11. Sungrazing comets: Probing the inner extremes of the Solar System

    NASA Astrophysics Data System (ADS)

    Knight, M.

    2014-07-01

    /Machholz 1. The third group, Meyer, has not been linked to any known solar system object and has an unknown orbital period. The remaining known sungrazing comets have a variety of orbits and, with the notable exception of ISON, are generally not observed extensively. Due to their extreme orbits, sungrazing comets offer unique opportunities for understanding evolutionary processes in our solar system. During their perihelion passages they experience equilibrium temperatures exceeding 1500 K, resulting in sublimation of their dust and potentially allowing the least volatile components of our solar system to be cataloged. In fact, while all of the near-Sun objects discovered by SOHO and STEREO are designated ''comets'', many of those not associated with other known cometary objects may be asteroids or defunct comets whose apparent activity at these distances is due to sublimation of their bare surfaces. Sungrazing comets also experience strong tidal forces, resulting in frequent fragmentation. Such breakups expose the unprocessed interiors, potentially allowing intercomparison of the compositions of discrete fragments and revealing the size distribution of the planetessimals out of which the parent comet formed. Finally, it has recently become possible to use comets as ''solar probes'', treating them as test particles that can reveal properties of the solar environment such as the coronal temperature and density, magnetic field strength, and solar wind speed and direction.

  12. Dedicated Cone-Beam CT System for Extremity Imaging

    PubMed Central

    Al Muhit, Abdullah; Zbijewski, Wojciech; Thawait, Gaurav K.; Stayman, J. Webster; Packard, Nathan; Senn, Robert; Yang, Dong; Foos, David H.; Yorkston, John; Siewerdsen, Jeffrey H.

    2014-01-01

    Purpose To provide initial assessment of image quality and dose for a cone-beam computed tomographic (CT) scanner dedicated to extremity imaging. Materials and Methods A prototype cone-beam CT scanner has been developed for imaging the extremities, including the weight-bearing lower extremities. Initial technical assessment included evaluation of radiation dose measured as a function of kilovolt peak and tube output (in milliampere seconds), contrast resolution assessed in terms of the signal difference–to-noise ratio (SDNR), spatial resolution semiquantitatively assessed by using a line-pair module from a phantom, and qualitative evaluation of cadaver images for potential diagnostic value and image artifacts by an expert CT observer (musculoskeletal radiologist). Results The dose for a nominal scan protocol (80 kVp, 108 mAs) was 9 mGy (absolute dose measured at the center of a CT dose index phantom). SDNR was maximized with the 80-kVp scan technique, and contrast resolution was sufficient for visualization of muscle, fat, ligaments and/or tendons, cartilage joint space, and bone. Spatial resolution in the axial plane exceeded 15 line pairs per centimeter. Streaks associated with x-ray scatter (in thicker regions of the patient—eg, the knee), beam hardening (about cortical bone—eg, the femoral shaft), and cone-beam artifacts (at joint space surfaces oriented along the scanning plane—eg, the interphalangeal joints) presented a slight impediment to visualization. Cadaver images (elbow, hand, knee, and foot) demonstrated excellent visibility of bone detail and good soft-tissue visibility suitable to a broad spectrum of musculoskeletal indications. Conclusion A dedicated extremity cone-beam CT scanner capable of imaging upper and lower extremities (including weight-bearing examinations) provides sufficient image quality and favorable dose characteristics to warrant further evaluation for clinical use. © RSNA, 2013 Online supplemental material is available for

  13. Investigation of LiF, Mg and Ti (TLD-100) Reproducibility

    PubMed Central

    Sadeghi, M.; Sina, S.; Faghihi, R.

    2015-01-01

    LiF, Mg and Ti cubical TLD chips (known as TLD-100) are widely used for dosimetry purposes. The repeatability of TL dosimetry is investigated by exposing them to doses of (81, 162 and 40.5 mGy) with 662keV photons of Cs-137. A group of 40 cubical TLD chips was randomly selected from a batch and the values of Element Correction Coefficient (ECC) were obtained 4 times by irradiating them to doses of 81 mGy (two times), 162mGy and 40.5mGy. Results of this study indicate that the average reproducibility of ECC calculation for 40 TLDs is 1.5%, while these values for all chips do not exceed 5%. PMID:26688801

  14. NOTE: Monte Carlo simulation of correction factors for IAEA TLD holders

    NASA Astrophysics Data System (ADS)

    Hultqvist, Martha; Fernández-Varea, José M.; Izewska, Joanna

    2010-03-01

    The IAEA standard thermoluminescent dosimeter (TLD) holder has been developed for the IAEA/WHO TLD postal dose program for audits of high-energy photon beams, and it is also employed by the ESTRO-QUALity assurance network (EQUAL) and several national TLD audit networks. Factors correcting for the influence of the holder on the TL signal under reference conditions have been calculated in the present work from Monte Carlo simulations with the PENELOPE code for 60Co γ-rays and 4, 6, 10, 15, 18 and 25 MV photon beams. The simulation results are around 0.2% smaller than measured factors reported in the literature, but well within the combined standard uncertainties. The present study supports the use of the experimentally obtained holder correction factors in the determination of the absorbed dose to water from the TL readings; the factors calculated by means of Monte Carlo simulations may be adopted for the cases where there are no measured data.

  15. Operational comparison of TLD albedo dosemeters and solid state nuclear tracks detectors in fuel fabrication facilities.

    PubMed

    Tsujimura, N; Takada, C; Yoshida, T; Momose, T

    2007-01-01

    The authors carried out an operational study that compared the use of TLD albedo dosemeters and solid state nuclear tracks detector in plutonium environments of Japan Nuclear Cycle Development Institute, Tokai Works. A selected group of workers engaged in the fabrication process of MOX (Plutonium-Uranium mixed oxide) fuel wore both TLD albedo dosemeters and solid state nuclear tracks detectors. The TL readings were generally proportional to the counted etch-pits, and thus the dose equivalent results obtained from TLD albedo dosemeter agreed with those from solid state nuclear tracks detector within a factor of 1.5. This result indicates that, in the workplaces of the MOX fuel plants, the neutron spectrum remained almost constant in terms of time and space, and the appropriate range of field-specific correction with spectrum variations was small in albedo dosimetry.

  16. Dosimetry quality assurance in Martin Marietta Energy Systems' centralized external dosimetry system

    SciTech Connect

    Souleyrette, M.L.

    1992-10-23

    External dosimetry needs at the four Martin Marietta Energy Systems facilities are served by Energy Systems Centralized External Dosimetry System (CEDS). The CEDS is a four plant program with four dosimeter distribution centers and two dosimeter processing centers. Each plant has its own distribution center, while processing centers are located at ORNL and the Y-12 Plant. The program has been granted accreditation by the Department of Energy Laboratory Accreditation Program (DOELAP). The CEDS is a TLD based system which is responsible for whole-body beta-gamma, neutron, and extremity monitoring. Beta-gamma monitoring is performed using the Harshaw/Solon Technologies model 8805 dosimeter. Effective October 1, 1992 the standard silver mylar has been replaced with an Avery mylar foil blackened on the underside with ink. This was done in an effort to reduce the number of light induced suspect readings. At this time we have little operational experience with the new blackened mylars-The CEDS neutron dosimeter is the Harshaw model 8806B. This card/holder configuration contains two TLD-600/TLD-700 chip pairs; one pair is located beneath a cadmium filter and one pair is located beneath a plastic filter. In routine personnel monitoring the CEDS neutron dosimeter is always paired with a CEDS beta-gamma dosimeter.The CEDS extremity dosimeter is composed of a Harshaw thin TLD-700 dosiclip placed inside a Teledyne RB-4 finger sachet. The finger sachet provides approximately 7 mg/cm[sup 2] filtration over the chip. A teflon ring surrounds the dosiclip to help prevent tearing of the vinyl sachet.

  17. Application of the TLD albedo technique for monitoring and interpretation of neutron stray radiation fields

    NASA Astrophysics Data System (ADS)

    Piesch, E.; Burgkhardt, B.

    1980-09-01

    A single sphere albedo technique with TLD 600/TLD 700 detectors has been applied in neutron monitoring to calibrate albedo dosimeters and to interpret neutron stray radiation fields in terms of neutron dose equivalent separated for the energy groups below 0.4 eV, 0.4-10 keV and 10 keV-10 MeV, and Eeff for fast neutrons. The paper describes the technique for field and personnel monitoring under the aspect of an on-line computer program for data recording and processing.

  18. Experimental investigation of utilizing TLD with baffles in a scaled down 5-story benchmark building

    NASA Astrophysics Data System (ADS)

    Zahrai, Seyed Mehdi; Abbasi, Saeed; Samali, Bijan; Vrcelj, Zora

    2012-01-01

    A tuned liquid damper (TLD) is a special type of auxiliary damping device, which relies on the sloshing of a liquid (water) in a container to counteract the forces acting on the structure. Damping in the TLD is introduced as a result of liquid sloshing and wave breaking. A conventional TLD is generally tuned to the main frequency of the building and is less efficient in other frequencies. Because of this limitation, the TLD is usually used to control the structural response of structures, which could be simulated as a SDOF structure, and mostly due to wind forces.In this paper a new kind of tuned liquid damper with some installed rotatable baffles is studied experimentally. The main idea behind installing such baffles is to compensate the effects of probable mistuning of the TLD and also it is an effort toward making the TLD more controllable, i.e. a semi-active damper.Response of a five story benchmark building was utilized to investigate the contributions of these baffles on efficiency of tuned liquid damper under dynamic and earthquake excitations. By observing the performance of TLD with baffles, the study investigates the influence of a number of parameters, include the following: baffles angles, frequency ratio, mass ratio and especially the effects of probable mistuning with changing the depth of water and orientation of baffles. The damping ratios of the building for a range of baffles angles were evaluated using logarithmic decrement technique. The results that are obtained in this paper show that the displacement and acceleration responses of the structure under the free vibration test utilizing the baffles reduced up to 2.5% and 3.9%, respectively, when compared with the case where no baffles are employed. Also the dynamic magnification factor under harmonic excitation reduced up to 2.7% proportional to baffles angles. Damping of the structure equipped with this type of TLD increased in a range of 3.93-6.38% when compared to the case of using no damper

  19. Pilot system on extreme climate monitoring and early warning for long range forecast in Korea

    NASA Astrophysics Data System (ADS)

    Cho, K.; Park, B. K.; E-hyung, P.; Gong, Y.; Kim, H. K.; Park, S.; Min, S. K.; Yoo, H. D.

    2015-12-01

    Recently, extreme weather/climate events such as heat waves, flooding/droughts etc. have been increasing in frequency and intensity under climate change over the world. Also, they can have substantial impacts on ecosystem and human society (agriculture, health, and economy) of the affected regions. According to future projections of climate, extreme weather and climate events in Korea are expected to occure more frequently with stronger intensity over the 21st century. For the better long range forecast, it is also fundamentally ruquired to develop a supporting system in terms of extreme weather and climate events including forequency and trend. In this context, the KMA (Korea Meteorological Administration) has recently initiated a development of the extreme climate monintoring and early warning system for long range forecast, which consists of three sub-system components; (1) Real-time climate monitoring system, (2) Ensemble prediction system, and (3) Mechanism analysis and display system for climate extremes. As a first step, a pilot system has been designed focusing on temperature extremes such heat waves and cold snaps using daily, monthly and seasonal observations and model prediction output on the global, regional and national levels. In parallel, the skills of the KMA long range prediction system are being evaluated comprehensively for weather and climate extremes, for which varous case studies are conducted to better understand the observed variations of extrem climates and responsible mechanisms and also to assess predictability of the ensemble prediction system for extremes. Details in the KMA extreme climate monitoring and early warning system will be intorduced and some preliminary results will be discussed for heat/cold waves in Korea.

  20. Data-driven prediction and prevention of extreme events in a spatially extended excitable system.

    PubMed

    Bialonski, Stephan; Ansmann, Gerrit; Kantz, Holger

    2015-10-01

    Extreme events occur in many spatially extended dynamical systems, often devastatingly affecting human life, which makes their reliable prediction and efficient prevention highly desirable. We study the prediction and prevention of extreme events in a spatially extended system, a system of coupled FitzHugh-Nagumo units, in which extreme events occur in a spatially and temporally irregular way. Mimicking typical constraints faced in field studies, we assume not to know the governing equations of motion and to be able to observe only a subset of all phase-space variables for a limited period of time. Based on reconstructing the local dynamics from data and despite being challenged by the rareness of events, we are able to predict extreme events remarkably well. With small, rare, and spatiotemporally localized perturbations which are guided by our predictions, we are able to completely suppress extreme events in this system.

  1. Investigation of TLD-700 energy response to low energy x-ray encountered in diagnostic radiology

    NASA Astrophysics Data System (ADS)

    Herrati, Ammar; Bourouina, Mourad; Khalal-Kouache, Karima

    2016-01-01

    The aim of thiswork is to study the energy dependence of thermoluminescent dosimeter (TLD-700) for low energy X-ray beams encountered in conventional diagnostic radiology. In the first step, we studied some characteristics (reproducibility and linearity) of TLD-700 chips using a 137Cs source, and selected TLD chips with reproducibility better than 2.5%. Then we determined TLD-700 energy response for diagnostic radiology X-ray qualities, and investigated its influence on air kerma estimate. A maximum deviation of 60% can be obtained if TLDs are calibrated for 137Cs radiation source and used in diagnostic radiology fields. However, this deviation became less than 20% if TLDs chips are calibrated for the reference x-ray radiation quality RQR5 (recommended by the IEC 61267 standard). Consequently, we recommend calibrating this kind of TLDdetector with RQR5 diagnostic radiology X-ray quality. This method permits to obtain a good accuracy when assessing the entrance dose in diagnostic radiology procedures.

  2. Relative Efficiency of TLD-100 to High Linear Energy Transfer Radiation: Correction to Astronaut Absorbed Dose

    NASA Technical Reports Server (NTRS)

    Badhwar, G. D.; Cash, B. L.; Semones, E. J.; Yasuda, H.; Fujitaka, K.

    1999-01-01

    Response of thermoluminescent detectors (TLD-100) to high linear energy transfer (LET) particles has been studied using helium, carbon, silicon, and iron ions from the Heavy Ion Medical Accelerator at Chiba (Japan), iron ions from the Brookhaven National Laboratory (NY) Alternate Gradient Synchrotron, and 53, 134, 185, and 232 MeV protons from the Loma Linda accelerator. Using the measured relative (to 137Cs) dose efficiency, and measured LET spectra from a tissue equivalent proportional counter (TEPC) on 20 Space Shuttle flights, and 7 Mir flights, the underestimation of absorbed dose by these detectors has been evaluated. The dose underestimation is between 15-20% depending upon the flight inclination and shielding location. This has been confirmed by direct correlation of measured dose by TEPC and TLD-100 at a low shielded location in the Shuttle mid-deck. A comparison of efficiency- LET data with a compilation of similar data from TLD-700, shows that shapes of the two curves are nearly identical, but that the TLD-100 curve is systematically lower by about 13%, and is the major cause of dose underestimation. These results strongly suggest that TLDs used for crew dose estimation be regularly calibrated using heavy ions.

  3. Relative Efficiency of TLD-100 to Linear Energy Transfer Radiation: Correction to Astronaut Absorbed Dose

    NASA Technical Reports Server (NTRS)

    Badhwar, Gautam D.; Cash, B. L.; Semones, E. J.; Yasuda, H.; Fujitaka, K.

    1999-01-01

    Response of thermoluminescent detectors (TLD-100) to high linear energy transfer (LET) particles has been studied using helium, carbon, silicon, and iron ions from the Heavy Ion Medical Accelerator at Chiba (Japan), iron ions from the Brookhaven National Laboratory (NY) Alternate Gradient Synchrotron, and 53, 134, 185, and 232 MeV protons from the Loma Linda accelerator. Using the measured relative (to (137)Cs dose efficiency, and measured LET spectra from a tissue equivalent proportional counter (TEPC) on 20 Space Shuttle flights, and 7 Mir flights, the underestimation of absorbed dose by these detectors has been evaluated. The dose underestimation is between 15-20% depending upon the flight inclination and shielding location. This has been confirmed by direct correlation of measured dose by TEPC and TLD-100 at a low shielded location in the Shuttle mid-deck. A comparison of efficiency- LET data with a compilation of similar data from TLD-700, shows that shapes of the two curves are nearly identical, but that the TLD-100 curve is systematically lower by about 13%, and is the major cause of dose underestimation. These results strongly suggest that TLDs used for crew dose estimation be regularly calibrated using heavy ions.

  4. Relative Efficiency of TLD-100 to Linear Energy Transfer Radiation: Correction to Astronaut Absorbed Dose

    NASA Technical Reports Server (NTRS)

    Badhwar, Gautam D.; Cash, B. L.; Semones, E. J.; Yasuda, H.; Fujitaka, K.

    1999-01-01

    Response of thermoluminescent detectors (TLD-100) to high linear energy transfer (LET) particles has been studied using helium, carbon, silicon, and iron ions from the Heavy Ion Medical Accelerator at Chiba (Japan), iron ions from the Brookhaven National Laboratory (NY) Alternate Gradient Synchrotron, and 53, 134, 185, and 232 MeV protons from the Loma Linda accelerator. Using the measured relative (to (137)Cs dose efficiency, and measured LET spectra from a tissue equivalent proportional counter (TEPC) on 20 Space Shuttle flights, and 7 Mir flights, the underestimation of absorbed dose by these detectors has been evaluated. The dose underestimation is between 15-20% depending upon the flight inclination and shielding location. This has been confirmed by direct correlation of measured dose by TEPC and TLD-100 at a low shielded location in the Shuttle mid-deck. A comparison of efficiency- LET data with a compilation of similar data from TLD-700, shows that shapes of the two curves are nearly identical, but that the TLD-100 curve is systematically lower by about 13%, and is the major cause of dose underestimation. These results strongly suggest that TLDs used for crew dose estimation be regularly calibrated using heavy ions.

  5. Systemic inflammation and cerebral palsy risk in extremely preterm infants

    PubMed Central

    Kuban, KCK; O’Shea, TM; Allred, EN; Paneth, N; Hirtz, D; Fichorova, RN; Leviton, A

    2013-01-01

    We hypothesized that among extremely preterm infants, elevated concentrations of inflammation-related proteins in neonatal blood are associated with cerebral palsy (CP) at 24 months. Methods In 939 infants born before 28 weeks gestation, we measured blood concentrations of 25 proteins on postnatal days 1, 7, and 14 and evaluated associations between elevated protein concentrations and CP diagnosis. Results Protein elevations within three days of birth were not associated with CP. Elevations of TNF-α, TNF-R1, IL-8, ICAM-1, on at least two days were associated with diparesis. Recurrent-persistent elevations of IL-6, E-SEL, or IGFBP-1 were associated with hemiparesis. Diparesis and hemiparesis were more likely among infants who had at least four of nine proteins elevations that previously have been associated with cognitive impairment and microcephaly. Interpretation Repeated elevations of inflammation-related proteins during the first two postnatal weeks are associated with increased risk of CP. PMID:24646503

  6. A single TLD dose algorithm to satisfy federal standards and typical field conditions

    SciTech Connect

    Stanford, N.; McCurdy, D.E. )

    1990-06-01

    Modern whole-body dosimeters are often required to accurately measure the absorbed dose in a wide range of radiation fields. While programs are commonly developed around the fields tested as part of the National Voluntary Accreditation Program (NVLAP), the actual fields of application may be significantly different. Dose algorithms designed to meet the NVLAP standard, which emphasizes photons and high-energy beta radiation, may not be capable of the beta-energy discrimination necessary for accurate assessment of absorbed dose in the work environment. To address this problem, some processors use one algorithm for NVLAP testing and one or more different algorithms for the work environments. After several years of experience with a multiple algorithm approach, the Dosimetry Services Group of Yankee Atomic Electric Company (YAEC) developed a one-algorithm system for use with a four-element TLD badge using Li2B4O7 and CaSO4 phosphors. The design of the dosimeter allows the measurement of the effective energies of both photon and beta components of the radiation field, resulting in excellent mixed-field capability. The algorithm was successfully tested in all of the NVLAP photon and beta fields, as well as several non-NVLAP fields representative of the work environment. The work environment fields, including low- and medium-energy beta radiation and mixed fields of low-energy photons and beta particles, are often more demanding than the NVLAP fields. This paper discusses the development of the algorithm as well as some results of the system testing including: mixed-field irradiations, angular response, and a unique test to demonstrate the stability of the algorithm. An analysis of the uncertainty of the reported doses under various irradiation conditions is also presented.

  7. A single TLD dose algorithm to satisfy federal standards and typical field conditions.

    PubMed

    Stanford, N; McCurdy, D E

    1990-06-01

    Modern whole-body dosimeters are often required to accurately measure the absorbed dose in a wide range of radiation fields. While programs are commonly developed around the fields tested as part of the National Voluntary Accreditation Program (NVLAP), the actual fields of application may be significantly different. Dose algorithms designed to meet the NVLAP standard, which emphasizes photons and high-energy beta radiation, may not be capable of the beta-energy discrimination necessary for accurate assessment of absorbed dose in the work environment. To address this problem, some processors use one algorithm for NVLAP testing and one or more different algorithms for the work environments. After several years of experience with a multiple algorithm approach, the Dosimetry Services Group of Yankee Atomic Electric Company (YAEC) developed a one-algorithm system for use with a four-element TLD badge using Li2B4O7 and CaSO4 phosphors. The design of the dosimeter allows the measurement of the effective energies of both photon and beta components of the radiation field, resulting in excellent mixed-field capability. The algorithm was successfully tested in all of the NVLAP photon and beta fields, as well as several non-NVLAP fields representative of the work environment. The work environment fields, including low- and medium-energy beta radiation and mixed fields of low-energy photons and beta particles, are often more demanding than the NVLAP fields. This paper discusses the development of the algorithm as well as some results of the system testing including: mixed-field irradiations, angular response, and a unique test to demonstrate the stability of the algorithm. An analysis of the uncertainty of the reported doses under various irradiation conditions is also presented.

  8. Extreme Cost Reductions with Multi-Megawatt Centralized Inverter Systems

    SciTech Connect

    Schwabe, Ulrich; Fishman, Oleg

    2015-03-20

    The objective of this project was to fully develop, demonstrate, and commercialize a new type of utility scale PV system. Based on patented technology, this includes the development of a truly centralized inverter system with capacities up to 100MW, and a high voltage, distributed harvesting approach. This system promises to greatly impact both the energy yield from large scale PV systems by reducing losses and increasing yield from mismatched arrays, as well as reduce overall system costs through very cost effective conversion and BOS cost reductions enabled by higher voltage operation.

  9. Sensitivity calibration of an imaging extreme ultraviolet spectrometer-detector system for determining the efficiency of broadband extreme ultraviolet sources

    NASA Astrophysics Data System (ADS)

    Fuchs, S.; Rödel, C.; Krebs, M.; Hädrich, S.; Bierbach, J.; Paz, A. E.; Kuschel, S.; Wünsche, M.; Hilbert, V.; Zastrau, U.; Förster, E.; Limpert, J.; Paulus, G. G.

    2013-02-01

    We report on the absolute sensitivity calibration of an extreme ultraviolet (XUV) spectrometer system that is frequently employed to study emission from short-pulse laser experiments. The XUV spectrometer, consisting of a toroidal mirror and a transmission grating, was characterized at a synchrotron source in respect of the ratio of the detected to the incident photon flux at photon energies ranging from 15.5 eV to 99 eV. The absolute calibration allows the determination of the XUV photon number emitted by laser-based XUV sources, e.g., high-harmonic generation from plasma surfaces or in gaseous media. We have demonstrated high-harmonic generation in gases and plasma surfaces providing 2.3 μW and μJ per harmonic using the respective generation mechanisms.

  10. Thorium Chemistry in Oxo-Tellurium System under Extreme Conditions.

    PubMed

    Xiao, Bin; Kegler, Philip; Bosbach, Dirk; Alekseev, Evgeny V

    2017-03-06

    Through the use of a high-temperature/high-pressure synthesis method, four thorium oxo-tellurium compounds with different tellurium valence states were isolated. The novel inorganic phases illustrate the intrinsic complexity of the actinide tellurium chemistry under extreme conditions of pressure and temperature. Th2Te3O11 is the first instance of a mixed-valent oxo-tellurium compound, and at the same time, Te exhibits three different coordination environments (Te(IV)O3, Te(IV)O4, and Te(VI)O6) within a single structure. These three types of Te polyhedra are further fused together, resulting in a [Te3O11](8-) fragment. Na4Th2(Te(VI)3O15) and K2Th(Te(VI)O4)3 are the first alkaline thorium tellurates described in the literature. Both compounds are constructed from ThO9 tricapped trigonal prisms and Te(VI)O6 octahedra. Na4Th2(Te(VI)3O15) is a three-dimensional framework based on Th2O15 and Te2O10 dimers, while K2Th(Te(VI)O4)3 contains tungsten oxide bronze like Te layers linked by ThO9 polyhedra. The structure of β-Th(Te(IV)O3)(SO4) is built from infinite thorium chains cross-linked by Te(IV)O3(2-) and SO4(2-) anions. Close structural analysis suggests that β-Th(Te(IV)O3)(SO4) is highly related to the structure of α-Th(SeO4)2. Additionally, the Raman spectra are recorded and the characteristic peaks are assigned based on a comparison of reported tellurites or tellurates.

  11. The National Integrated Heat Health Information System (NIHHIS) as a Learning System for Extreme Heat: Evolving Future Resilience from Present Climate Extremes

    NASA Astrophysics Data System (ADS)

    Jones, H.; Trtanj, J.; Pulwarty, R. S.; Higgins, W.

    2016-12-01

    There is presently no consensus indicator for the effect of extreme heat on human health. At the early warning timescale, a variety of approaches to setting temperature thresholds (minimum, maximum, time-lagged) or more complex approaches (Heat Index, Thermal Comfort, etc...) for issuing alerts and warnings have been recommended by literature and implemented, leading to much heterogeneity. At longer timescales, efforts have been made to quantify potential future health outcomes using climate projections, but nonstationarity of the climate system, economy, and demography may invalidate many of the assumptions which were necessarily made in these studies. Furthermore, in our pursuit of developing the best models and indicators to represent the impacts of climate extremes, perhaps we have not paid enough attention to what makes them policy-relevant, responsive to changing assumptions, and targeted at elements that can actually be predicted. In response to this concern, a comprehensive approach to improving the impactfulness of these indicators is underway as part of the National Integrated Heat Health Information System (NIHHIS), which was initiated by NOAA and CDC, but has grown to include many other federal agency and non-governmental partners. NIHHIS is a framework that integrates what we know about extreme heat and health outcomes within a learning system - simultaneously informing early warning and long-term risk reduction prior to, during, and while recovering from extreme heat events. NIHHIS develops impactful evolutionary responses to climate extremes. Through ongoing regional engagements, we are applying the lessons of impact modeling studies to create learning systems in the Southwest, Northeast, Midwest, and soon other regions of the U.S. This session will provide a view of this process as it has been carried out in the Southwest region - focused on the transboundary (US-Mexico) region around El Paso, Texas, and the NIHHIS approach to indicators overall.

  12. Extreme AO Observations of Two Triple Asteroid Systems with SPHERE

    NASA Astrophysics Data System (ADS)

    Yang, B.; Wahhaj, Z.; Beauvalet, L.; Marchis, F.; Dumas, C.; Marsset, M.; Nielsen, E. L.; Vachier, F.

    2016-04-01

    We present the discovery of a new satellite of asteroid (130) Elektra—S/2014 (130) 1—in differential imaging and in integral field spectroscopy data over multiple epochs obtained with Spectro-Polarimetric High-contrast Exoplanet Research/Very Large Telescope. This new (second) moonlet of Elektra is about 2 km across, on an eccentric orbit, and about 500 km away from the primary. For a comparative study, we also observed another triple asteroid system, (93) Minerva. For both systems, component-resolved reflectance spectra of the satellites and primary were obtained simultaneously. No significant spectral difference was observed between the satellites and the primary for either triple system. We find that the moonlets in both systems are more likely to have been created by sub-disruptive impacts as opposed to having been captured.

  13. EXTREME AO OBSERVATIONS OF TWO TRIPLE ASTEROID SYSTEMS WITH SPHERE

    SciTech Connect

    Yang, B.; Wahhaj, Z.; Dumas, C.; Marsset, M.; Beauvalet, L.; Marchis, F.; Nielsen, E. L.; Vachier, F.

    2016-04-01

    We present the discovery of a new satellite of asteroid (130) Elektra—S/2014 (130) 1—in differential imaging and in integral field spectroscopy data over multiple epochs obtained with Spectro-Polarimetric High-contrast Exoplanet Research/Very Large Telescope. This new (second) moonlet of Elektra is about 2 km across, on an eccentric orbit, and about 500 km away from the primary. For a comparative study, we also observed another triple asteroid system, (93) Minerva. For both systems, component-resolved reflectance spectra of the satellites and primary were obtained simultaneously. No significant spectral difference was observed between the satellites and the primary for either triple system. We find that the moonlets in both systems are more likely to have been created by sub-disruptive impacts as opposed to having been captured.

  14. Woven Thermal Protection System (Woven TPS) for Extreme Entry Environments

    NASA Image and Video Library

    The Woven Thermal Protection System (WTPS) project explores an innovative way to design, develop and manufacture a family of ablative TPS materials using weaving technology and testing them in the ...

  15. Extreme phase sensitivity in systems with fractal isochrons

    NASA Astrophysics Data System (ADS)

    Mauroy, A.; Mezić, I.

    2015-07-01

    Sensitivity to initial conditions is usually associated with chaotic dynamics and strange attractors. However, even systems with (quasi)periodic dynamics can exhibit it. In this context we report on the fractal properties of the isochrons of some continuous-time asymptotically periodic systems. We define a global measure of phase sensitivity that we call the phase sensitivity coefficient and show that it is an invariant of the system related to the capacity dimension of the isochrons. Similar results are also obtained with discrete-time systems. As an illustration of the framework, we compute the phase sensitivity coefficient for popular models of bursting neurons, suggesting that some elliptic bursting neurons are characterized by isochrons of high fractal dimensions and exhibit a very sensitive (unreliable) phase response.

  16. Scalable PGAS Metadata Management on Extreme Scale Systems

    SciTech Connect

    Chavarría-Miranda, Daniel; Agarwal, Khushbu; Straatsma, TP

    2013-05-16

    Programming models intended to run on exascale systems have a number of challenges to overcome, specially the sheer size of the system as measured by the number of concurrent software entities created and managed by the underlying runtime. It is clear from the size of these systems that any state maintained by the programming model has to be strictly sub-linear in size, in order not to overwhelm memory usage with pure overhead. A principal feature of Partitioned Global Address Space (PGAS) models is providing easy access to global-view distributed data structures. In order to provide efficient access to these distributed data structures, PGAS models must keep track of metadata such as where array sections are located with respect to processes/threads running on the HPC system. As PGAS models and applications become ubiquitous on very large transpetascale systems, a key component to their performance and scalability will be efficient and judicious use of memory for model overhead (metadata) compared to application data. We present an evaluation of several strategies to manage PGAS metadata that exhibit different space/time tradeoffs. We use two real-world PGAS applications to capture metadata usage patterns and gain insight into their communication behavior.

  17. Exploring Asynchronous Many-Task Runtime Systems toward Extreme Scales

    SciTech Connect

    Knight, Samuel; Baker, Gavin Matthew; Gamell, Marc; Hollman, David; Sjaardema, Gregor; Kolla, Hemanth; Teranishi, Keita; Wilke, Jeremiah J; Slattengren, Nicole; Bennett, Janine Camille

    2015-10-01

    Major exascale computing reports indicate a number of software challenges to meet the dramatic change of system architectures in near future. While several-orders-of-magnitude increase in parallelism is the most commonly cited of those, hurdles also include performance heterogeneity of compute nodes across the system, increased imbalance between computational capacity and I/O capabilities, frequent system interrupts, and complex hardware architectures. Asynchronous task-parallel programming models show a great promise in addressing these issues, but are not yet fully understood nor developed su ciently for computational science and engineering application codes. We address these knowledge gaps through quantitative and qualitative exploration of leading candidate solutions in the context of engineering applications at Sandia. In this poster, we evaluate MiniAero code ported to three leading candidate programming models (Charm++, Legion and UINTAH) to examine the feasibility of these models that permits insertion of new programming model elements into an existing code base.

  18. Novel Hydrogen Production Systems Operative at Thermodynamic Extremes

    SciTech Connect

    Gunsalus, Robert

    2012-11-30

    We have employed a suite of molecular, bioinformatics, and biochemical tools to interrogate the thermodynamically limiting steps of H{sub 2} production from fatty acids in syntrophic communities. We also developed a new microbial model system that generates high H{sub 2} concentrations (over 17% of the gas phase) with high H{sub 2} yields of over 3 moles H{sub 2} per mole glucose. Lastly, a systems-based study of biohydrogen production in model anaerobic consortia was performed to begin identifying key regulated steps as a precursor to modeling co-metabolism. The results of these studies significantly expand our ability to predict and model systems for H{sub 2} production in novel anaerobes that are currently very poorly documented or understood.

  19. Power System Extreme Event Detection: The VulnerabilityFrontier

    SciTech Connect

    Lesieutre, Bernard C.; Pinar, Ali; Roy, Sandip

    2007-10-17

    In this work we apply graph theoretic tools to provide aclose bound on a frontier relating the number of line outages in a gridto the power disrupted by the outages. This frontier describes theboundary of a space relating the possible severity of a disturbance interms of power disruption, from zero to some maximum on the boundary, tothe number line outages involved in the event. We present the usefulnessof this analysis with a complete analysis of a 30 bus system, and presentresults for larger systems.

  20. Microwave tomography of extremities: 1. Dedicated 2D system and physiological signatures

    NASA Astrophysics Data System (ADS)

    Semenov, Serguei; Kellam, James; Sizov, Yuri; Nazarov, Alexei; Williams, Thomas; Nair, Bindu; Pavlovsky, Andrey; Posukh, Vitaly; Quinn, Michael

    2011-04-01

    Microwave tomography (MWT) is a novel imaging modality which might be applicable for non-invasive assessment of functional and pathological conditions of biological tissues. Imaging of the soft tissue of extremities is one of its potential applications. The feasibility of this technology for such applications was demonstrated earlier. This is the first of two companion papers focused on an application of MWT for imaging of the extremity's soft tissues. The goal of this study is to assess the technical performance of the developed 2D MWT system dedicated for imaging of functional and pathological conditions of the extremity's soft tissues. Specifically, the system's performance was tested by its ability to detect signals associated with physiological activity and soft tissue interventions (circulatory related changes, blood flow reduction and a simulated compartmental syndrome)—the so-called physiological signatures. The developed 2D MWT system dedicated to the imaging of animal extremities demonstrates good technical performance allowing for stable and predictable data acquisition with reasonable agreement between the experimentally measured electromagnetic (EM) field and the simulated EM field within a measurement domain. Using the system, we were able to obtain physiological signatures associated with systolic versus diastolic phases of circulation in an animal extremity, reperfusion versus occlusion phases of the blood supply to the animal's extremity and a compartment syndrome. The imaging results are presented and discussed in the second companion paper.

  1. 78 FR 6811 - Country Code Top-Level Domain (ccTLD) for the United States; Policies and Requirements; Comments...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-31

    ... subcontracted administration of the usTLD to the Information Sciences Institute of the University of Southern.... Nexus requirement by providing proof of a bona fide presence or residence within the United States.\\7...

  2. Extreme Environments and Extreme Science: Reliability and Risk Assessment for Autonomous Systems with Application to Polar Campaigns

    NASA Astrophysics Data System (ADS)

    Trembanis, A.; Griffiths, G.

    2006-12-01

    Assessment of reliability and consequent risk to autonomous systems is an increasingly common and critical concern given the number of challenging new extreme environment research programs calling for the utilization of autonomous systems (e.g. AUVs, gliders, floats, etc.). The interest in using autonomous systems amongst the scientific community is particularly strong amongst polar research programs where so much vital area lies beyond the reach of traditional approaches. Therefore, the potential for scientific discovery is significantly increased, because of the very ability of autonomous systems to get to and gather information in the critical zones. The scientific merits and rewards of polar research are great but so too are the risks. There are risks both to mission success (i.e. science delivery) and risks to asset survival and recovery (i.e. retrieval). In polar settings the greatest increased risks are the complexities of operation (e.g. launch/recovery and retrieval) associated with sea ice and shelf ice. Even in open water settings the temporal and spatial dynamics of environmental conditions complicate the operation of autonomous systems. Very little systematic study and quantitative analysis has been conducted to evaluate the reliability and risk to autonomous systems in any operational setting let alone the demanding and increasingly sought after polar environments. Here we present some assessments of AUV reliability for polar and also non-polar settings drawing largely on datasets from both a large autonomous vehicle program (Autosub) and a small autonomous vehicle program (DOERRI) in order to illustrate key and common elements of reliability and risk that may provide insights to scientific end-users (PIs), program managers, and the developers and operators of other similar autonomous systems working in polar settings. An approach to risk management is laid out. Key risk mitigation elements are presented in categories of system stability and

  3. Reflective optical imaging system for extreme ultraviolet wavelengths

    DOEpatents

    Viswanathan, Vriddhachalam K.; Newnam, Brian E.

    1993-01-01

    A projection reflection optical system has two mirrors in a coaxial, four reflection configuration to reproduce the image of an object. The mirrors have spherical reflection surfaces to provide a very high resolution of object feature wavelengths less than 200 .mu.m, and preferably less than 100 .mu.m. An image resolution of features less than 0.05-0.1 .mu.m, is obtained over a large area field; i.e., 25.4 mm .times.25.4 mm, with a distortion less than 0.1 of the resolution over the image field.

  4. Reflective optical imaging system for extreme ultraviolet wavelengths

    DOEpatents

    Viswanathan, V.K.; Newnam, B.E.

    1993-05-18

    A projection reflection optical system has two mirrors in a coaxial, four reflection configuration to reproduce the image of an object. The mirrors have spherical reflection surfaces to provide a very high resolution of object feature wavelengths less than 200 [mu]m, and preferably less than 100 [mu]m. An image resolution of features less than 0.05-0.1 [mu]m, is obtained over a large area field; i.e., 25.4 mm [times] 25.4 mm, with a distortion less than 0.1 of the resolution over the image field.

  5. Reflective optical imaging system for extreme ultraviolet wavelengths

    SciTech Connect

    Viswanathan, V.K.; Newnam, B.E.

    1991-12-31

    This invention is comprised of a projection reflection optical system having two mirrors in a coaxial, four reflection configuration to reproduce the image of an object. The mirrors have aspherical reflection surfaces to provide a very high resolution of object feature wavelengths less than 200 {mu}m, and preferably less than 100 {mu}m. An image resolution of features less than 0.05--0.1 {mu}m, is obtained over a large area field; i.e., 25.4 mm {times} 25.4 mm, with a distortion less than 0.1 of the resolution over the image field.

  6. The GOCF/AWAP system - forecasting temperature extremes

    NASA Astrophysics Data System (ADS)

    Fawcett, Robert; Hume, Timothy

    2010-08-01

    Gridded hourly temperature forecasts from the Bureau of Meteorology's Gridded Operational Consensus Forecasting (GOCF) system are combined in real time with the Australian Water Availability Project (AWAP) gridded daily temperature analyses to produce gridded daily maximum and minimum temperature forecasts with lead times from one to five days. These forecasts are compared against the historical record of AWAP daily temperature analyses (1911 to present), to identify regions where record or near-record temperatures are predicted to occur. This paper describes the GOCF/AWAP system, showing how the daily maximum and minimum temperature forecasts are prepared from the hourly forecasts, and how they are bias-corrected in real time using the AWAP analyses, against which they are subsequently verified. Using monthly climatologies of long-term daily mean, standard deviation and all-time highest and lowest on record, derived forecast products (for both maximum and minimum temperature) include ordinary and standardised anomalies, "forecast - highest on record" and "forecast - lowest on record". Compensation for the climatological variation across the country is achieved in these last two products, which provide the necessary guidance as to whether or not record-breaking temperatures are expected, by expressing the forecast departure from the previous record in both °C and standard deviations.

  7. Extremal entanglement and mixedness in continuous variable systems

    SciTech Connect

    Adesso, Gerardo; Serafini, Alessio; Illuminati, Fabrizio

    2004-08-01

    We investigate the relationship between mixedness and entanglement for Gaussian states of continuous variable systems. We introduce generalized entropies based on Schatten p norms to quantify the mixedness of a state and derive their explicit expressions in terms of symplectic spectra. We compare the hierarchies of mixedness provided by such measures with the one provided by the purity (defined as tr {rho}{sup 2} for the state {rho}) for generic n-mode states. We then review the analysis proving the existence of both maximally and minimally entangled states at given global and marginal purities, with the entanglement quantified by the logarithmic negativity. Based on these results, we extend such an analysis to generalized entropies, introducing and fully characterizing maximally and minimally entangled states for given global and local generalized entropies. We compare the different roles played by the purity and by the generalized p entropies in quantifying the entanglement and the mixedness of continuous variable systems. We introduce the concept of average logarithmic negativity, showing that it allows a reliable quantitative estimate of continuous variable entanglement by direct measurements of global and marginal generalized p entropies.

  8. Dynamical systems proxies of atmospheric predictability and mid-latitude extremes

    NASA Astrophysics Data System (ADS)

    Messori, Gabriele; Faranda, Davide; Caballero, Rodrigo; Yiou, Pascal

    2017-04-01

    Extreme weather ocurrences carry enormous social and economic costs and routinely garner widespread scientific and media coverage. Many extremes (for e.g. storms, heatwaves, cold spells, heavy precipitation) are tied to specific patterns of midlatitude atmospheric circulation. The ability to identify these patterns and use them to enhance the predictability of the extremes is therefore a topic of crucial societal and economic value. We propose a novel predictability pathway for extreme events, by building upon recent advances in dynamical systems theory. We use two simple dynamical systems metrics - local dimension and persistence - to identify sets of similar large-scale atmospheric flow patterns which present a coherent temporal evolution. When these patterns correspond to weather extremes, they therefore afford a particularly good forward predictability. We specifically test this technique on European winter temperatures, whose variability largely depends on the atmospheric circulation in the North Atlantic region. We find that our dynamical systems approach provides predictability of large-scale temperature extremes up to one week in advance.

  9. TLD efficiency of 7LiF for doses deposited by high-LET particles

    NASA Technical Reports Server (NTRS)

    Benton, E. R.; Frank, A. L.; Benton, E. V.

    2000-01-01

    The efficiency of 7 LiF TLDs (TLD-700) in registering dose from high-LET (> or = 10 keV/micrometers) charged particles (relative to 137Cs gamma rays) has been measured for a number of accelerated heavy ions at various particle accelerator facilities. These measured efficiency values have been compared with similar results obtained from the open literature and a dose efficiency function has been fitted to the combined data set. While it was found that the dose efficiency is not only a function of LET, but also of the charge of the incident particle, the fitted function can be used to correct the undermeasured value of dose from exposures made in mixed radiation fields where LET information is available. This LET-dependent dose efficiency function is used in our laboratory in determining total absorbed dose and dose equivalent from combined TLD and CR-39 plastic nuclear track detector measurements.

  10. TLD efficiency of 7LiF for doses deposited by high-LET particles

    NASA Technical Reports Server (NTRS)

    Benton, E. R.; Frank, A. L.; Benton, E. V.

    2000-01-01

    The efficiency of 7 LiF TLDs (TLD-700) in registering dose from high-LET (> or = 10 keV/micrometers) charged particles (relative to 137Cs gamma rays) has been measured for a number of accelerated heavy ions at various particle accelerator facilities. These measured efficiency values have been compared with similar results obtained from the open literature and a dose efficiency function has been fitted to the combined data set. While it was found that the dose efficiency is not only a function of LET, but also of the charge of the incident particle, the fitted function can be used to correct the undermeasured value of dose from exposures made in mixed radiation fields where LET information is available. This LET-dependent dose efficiency function is used in our laboratory in determining total absorbed dose and dose equivalent from combined TLD and CR-39 plastic nuclear track detector measurements.

  11. Optimum parameters of TLD100 powder used for radiotherapy beams calibration check

    SciTech Connect

    Arib, M. . E-mail: mehenna.arib@comena-dz.org; Yaich, A.; Messadi, A.; Dari, F.

    2006-10-01

    External audit of the absorbed dose determination from radiotherapy machines is performed using Lithium fluoride (LiF) TLD-100. Optimal parameters needed to obtain highly accurate dosage from LiF powder was investigated, including the setup of the Harshaw 4000 reader. A linear correspondence between the thermoluminescent signal and the mass of the powder was observed, demonstrating that the dose can be evaluated with small samples of powder. The reproducibility of the thermoluminescence dosimeter (TLD) readings obtained with up to 10 samples from 1 capsule containing 160 mg of powder was around 1.5% (1 standard deviation [SD]). The time required for the manual evaluation of TLDs can be improved by 3 readings without loss of accuracy. Better reproducibility is achieved if the capsules are evaluated 7 days after irradiation using a nitrogen flow of 300 cc/min.

  12. Study of the glow curves of TLD exposed to thermal neutrons.

    PubMed

    Triolo, A; Brai, M; Marrale, M; Gennaro, G; Bartolotta, A

    2007-01-01

    The glow curves of thermoluminescent dosimeters (TLD600, TLD700 and MCP), exposed to a mixed field of thermal neutrons and gamma photons are analysed. The fluence values of thermal neutrons used, comparable with those used in radiotherapy, allow one to define the reliability of the TLDs, in particular the most sensitive MCP, in this radiation field and to get information on the dose absorbed values. The glow curves obtained have been deconvoluted using general order kinetics and the observed differences for the different LET components have been analysed. In particular, the ratio of the n(0) parameter of two different peaks seems to allow to discriminate the different contributions of neutrons and gamma photons in the beam.

  13. Radiological properties of plastics and TLD materials its application in radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Jabaseelan Samuel, E. James; Srinivasan, K.; Poopathi, V.

    2017-05-01

    In the current study, we evaluated the tissue equivalency of nine different commonly used thermoluminescence compounds and six plastic materials over the photon energy range of 15 KeV to 20 MeV. Our result confirmed that the ratio of number of electrons per gram, electron density of the entire TLD compounds and plastic materials to ICRU-44 soft tissue was lesser than unity, except in the case of polypropylene plastics. The effective atomic number ratio of all the plastic materials was also <1 excluding Poly-vinyl-chloride, and for TLD lithium borate material, it was <1 others which showed the deviation with respect to photon energy. Mass attenuation coefficient (µ/ϼ), mass absorption coefficient (µen/ρ) was calculated and the results are discussed in this paper.

  14. Difficulty with daily activities involving the lower extremities in people with systemic sclerosis.

    PubMed

    Poole, Janet L; Brandenstein, Jane

    2016-02-01

    The purpose of this study was to examine the extent of lower extremity impairments in motion and strength in people with systemic sclerosis and the relationships of the impairments to limitations in activities of daily living primarily involving the lower extremities. Participants were 69 persons with SSc who received evaluations of lower extremity joint motion (Keitel function test), strength (timed-stands test), and basic mobility (timed up and go test) and completed a demographic questionnaire regarding symptoms in the lower extremities. Activity limitations were measured by the Rheumatoid and Arthritis Outcome Score (RAOS) which examines functional ability, pain, and quality of life. The participants had difficulty with items requiring external rotation of the hips and lower extremity strength. There were moderate correlations between the impairment measures of joint motion, strength, mobility, and activity limitations. Fair correlations were found between the skin scores and the RAOS sections except for pain. The results of this study show that lower extremity involvement is present in persons with SSc. The findings, regarding strength, mobility, and joint motion are related to the ability to perform everyday activities involving the lower extremities, suggest that these areas should be targeted for intervention in persons with SSc.

  15. Evaluation of LiF:Mg,Ti (TLD-100) for Intraoperative Electron Radiation Therapy Quality Assurance

    PubMed Central

    Liuzzi, Raffaele; Savino, Federica; D’Avino, Vittoria; Pugliese, Mariagabriella; Cella, Laura

    2015-01-01

    Background Purpose of the present work was to investigate thermoluminescent dosimeters (TLDs) response to intraoperative electron radiation therapy (IOERT) beams. In an IOERT treatment, a large single radiation dose is delivered with a high dose-per-pulse electron beam (2–12 cGy/pulse) during surgery. To verify and to record the delivered dose, in vivo dosimetry is a mandatory procedure for quality assurance. The TLDs feature many advantages such as a small detector size and close tissue equivalence that make them attractive for IOERT as in vivo dosimeters. Methods LiF:Mg,Ti dosimeters (TLD-100) were irradiated with different IOERT electron beam energies (5, 7 and 9 MeV) and with a 6 MV conventional photon beam. For each energy, the TLDs were irradiated in the dose range of 0–10 Gy in step of 2Gy. Regression analysis was performed to establish the response variation of thermoluminescent signals with dose and energy. Results The TLD-100 dose-response curves were obtained. In the dose range of 0–10 Gy, the calibration curve was confirmed to be linear for the conventional photon beam. In the same dose region, the quadratic model performs better than the linear model when high dose-per-pulse electron beams were used (F test; p<0.05). Conclusions This study demonstrates that the TLD dose response, for doses ≤10Gy, has a parabolic behavior in high dose-per-pulse electron beams. TLD-100 can be useful detectors for IOERT patient dosimetry if a proper calibration is provided. PMID:26427065

  16. Response of TLD-albedo and nuclear track dosimeters exposed to plutonium sources

    SciTech Connect

    Brackenbush, L.W.; Baumgartner, W.V.; Fix, J.J.

    1991-12-01

    Neutron dosimetry has been extensively studied at Hanford since the mid-1940s. At the present time, Hanford contractors use thermoluminescent dosimeter (TLD)-albedo dosimeters to record the neutron dose equivalent received by workers. The energy dependence of the TLD-albedo dosimeter has been recognized and documented since introduced at Hanford in 1964 and numerous studies have helped assure the accuracy of dosimeters. With the recent change in Hanford`s mission, there has been a significant decrease in the handling of plutonium tetrafluoride, and an increase in the handling of plutonium metal and plutonium oxide sources. This study was initiated to document the performance of the current Hanford TLD-albedo dosimeter under the low scatter conditions of the calibration laboratory and under the high scatter conditions in the work place under carefully controlled conditions at the Plutonium Finishing Plant (PFP). The neutron fields at the PFP facility were measured using a variety of instruments, including a multisphere spectrometer, tissue equivalent proportional counters, and specially calibrated rem meters. Various algorithms were used to evaluate the TLD-albedo dosimeters, and the results are given in this report. Using current algorithms, the dose equivalents evaluated for bare sources and sources with less than 2.5 cm (1 in.) of acrylic plastic shielding in high scatter conditions typical of glove box operations are reasonably accurate. Recently developed CR-39 track etch dosimeters (TEDs) were also exposed in the calibration laboratory and at the PFP. The results indicate that the TED dosimeters are quite accurate for both bare and moderated neutron sources. Until personnel dosimeter is available that incorporates a direct measure of the neutron dose to a person, technical uncertainties in the accuracy of the recorded data will continue.

  17. Response of TLD-albedo and nuclear track dosimeters exposed to plutonium sources

    SciTech Connect

    Brackenbush, L.W.; Baumgartner, W.V.; Fix, J.J.

    1991-12-01

    Neutron dosimetry has been extensively studied at Hanford since the mid-1940s. At the present time, Hanford contractors use thermoluminescent dosimeter (TLD)-albedo dosimeters to record the neutron dose equivalent received by workers. The energy dependence of the TLD-albedo dosimeter has been recognized and documented since introduced at Hanford in 1964 and numerous studies have helped assure the accuracy of dosimeters. With the recent change in Hanford's mission, there has been a significant decrease in the handling of plutonium tetrafluoride, and an increase in the handling of plutonium metal and plutonium oxide sources. This study was initiated to document the performance of the current Hanford TLD-albedo dosimeter under the low scatter conditions of the calibration laboratory and under the high scatter conditions in the work place under carefully controlled conditions at the Plutonium Finishing Plant (PFP). The neutron fields at the PFP facility were measured using a variety of instruments, including a multisphere spectrometer, tissue equivalent proportional counters, and specially calibrated rem meters. Various algorithms were used to evaluate the TLD-albedo dosimeters, and the results are given in this report. Using current algorithms, the dose equivalents evaluated for bare sources and sources with less than 2.5 cm (1 in.) of acrylic plastic shielding in high scatter conditions typical of glove box operations are reasonably accurate. Recently developed CR-39 track etch dosimeters (TEDs) were also exposed in the calibration laboratory and at the PFP. The results indicate that the TED dosimeters are quite accurate for both bare and moderated neutron sources. Until personnel dosimeter is available that incorporates a direct measure of the neutron dose to a person, technical uncertainties in the accuracy of the recorded data will continue.

  18. Comments on ``large enhancement of TLD-100 sensitivity by irradiation in a reactor core''

    NASA Astrophysics Data System (ADS)

    Lakshmanan, A. R.; Chandra, Bhuwan; Bhatt, R. C.

    1987-06-01

    The large enhancement of TLD-100 sensitivity on irradiation in a reactor core reported by Lau et al. [Nucl. Instr. and Meth. B17 (1986) 170] is false and is in complete contradiction with the results reported earlier in the literature and with our recent findings. Lau et al. have misinterpreted the TL signal from thermal neutron induced 3H betas in LiF as due to enhanced TL sensitivity because of neutron induced traps/luminescent centres.

  19. Extremely sensitive dual imaging system in solid phantoms

    NASA Astrophysics Data System (ADS)

    Barnoy, Eran A.; Fixler, Dror; Popovtzer, Rachela; Nayhoz, Tsviya; Ray, Krishanu

    2016-03-01

    Herein we describe promising results from the combination of fluorescent lifetime imaging microscopy (FLIM) and diffusion reflection (DR) medical imaging techniques. Three different geometries of gold nanoparticles (GNPs) were prepared: spheres of 20nm diameter, rods (GNRs) of aspect ratio (AR) 2.5, and GNRs of AR 3.3. Each GNP geometry was then conjugated using PEG linkers estimated to be 10nm in length to each of 3 different fluorescent dyes: Fluorescein, Rhodamine B, and Sulforhodamine B. DR provided deep-volume measurements (up to 1cm) from within solid, tissue-imitating phantoms, indicating GNR presence corresponding to the light used by recording light scattered from the GNPs with increasing distance to a photodetector. FLIM imaged solutions as well as phantom surfaces, recording both the fluorescence lifetimes as well as the fluorescence intensities. Fluorescence quenching was observed for Fluorescein, while metal-enhanced fluorescence (MEF) was observed in Rhodamine B and Sulforhodamine B - the dyes with an absorption peak at a slightly longer wavelength than the GNP plasmon resonance peak. Our system is highly sensitive due to the increased intensity provided by MEF, and also because of the inherent sensitivity of both FLIM and DR. Together, these two modalities and MEF can provide a lot of meaningful information for molecular and functional imaging of biological samples.

  20. Seasonal forecasting of global hydrologic extremes using the North American Multi-model Ensemble system

    NASA Astrophysics Data System (ADS)

    Wood, Eric F.; Yuan, Xing; Roundy, Joshua K.; Sheffield, Justin

    2015-04-01

    Seasonal hydrologic extremes in the form of droughts and wet spells have devastating impacts on human and natural systems. Improving our understanding and predictive capability of hydrologic extremes, and facilitating adaptations through establishing climate service systems at regional to global scales, are among the grand challenges proposed by the World Climate Research Programme (WCRP), and are the core themes of the Regional Hydroclimate Projects (RHP) under the Global Energy and Water Exchanges Project (GEWEX). An experimental global seasonal hydrologic forecasting system has been developed, which is based on coupled climate forecast models participating in the North American Multi-Model Ensemble (NMME) project and an advanced land surface hydrologic model. The system is evaluated over major GEWEX/RHP river basins by comparing with Ensemble Streamflow Prediction (ESP). The multi-model seasonal forecast system provides higher detectability for soil moisture droughts, more reliable low and high flow ensemble forecasts, and better "real-time" prediction for the 2012 North American extreme drought. The association of the onset of extreme hydrologic events with oceanic and land precursors is also investigated based on the joint distribution of forecasts and observations. Climate models have a higher probability of missing the onset of hydrologic extremes when there is no oceanic precursor. But oceanic precursor alone is insufficient to guarantee a correct forecast, a land precursor is also critical in avoiding a false alarm for forecasting extremes. This study is targeted at providing the scientific underpinning for the predictability of hydrologic extremes over GEWEX/RHP basins, and serves as a prototype for seasonal hydrologic forecasts within the Global Framework for Climate Services (GFCS).

  1. Dose rate dependence for different dosimeters and detectors: TLD, OSL, EBT films, and diamond detectors

    SciTech Connect

    Karsch, L.; Beyreuther, E.; Burris-Mog, T.; Kraft, S.; Richter, C.; Zeil, K.; Pawelke, J.

    2012-05-15

    Purpose: The use of laser accelerators in radiation therapy can perhaps increase the low number of proton and ion therapy facilities in some years due to the low investment costs and small size. The laser-based acceleration technology leads to a very high peak dose rate of about 10{sup 11} Gy/s. A first dosimetric task is the evaluation of dose rate dependence of clinical dosimeters and other detectors. Methods: The measurements were done at ELBE, a superconductive linear electron accelerator which generates electron pulses with 5 ps length at 20 MeV. The different dose rates are reached by adjusting the number of electrons in one beam pulse. Three clinical dosimeters (TLD, OSL, and EBT radiochromic films) were irradiated with four different dose rates and nearly the same dose. A faraday cup, an integrating current transformer, and an ionization chamber were used to control the particle flux on the dosimeters. Furthermore two diamond detectors were tested. Results: The dosimeters are dose rate independent up to 410{sup 9} Gy/s within 2% (OSL and TLD) and up to 1510{sup 9} Gy/s within 5% (EBT films). The diamond detectors show strong dose rate dependence. Conclusions: TLD, OSL dosimeters, and EBT films are suitable for pulsed beams with a very high pulse dose rate like laser accelerated particle beams.

  2. Advancing the adaptive capacity of social-ecological systems to absorb climate extremes

    NASA Astrophysics Data System (ADS)

    Thonicke, Kirsten; Bahn, Michael; Bardgett, Richard; Bloemen, Jasper; Chabay, Ilan; Erb, Karlheinz; Giamberini, Mariasilvia; Gingrich, Simone; Lavorel, Sandra; Liehr, Stefan; Rammig, Anja

    2017-04-01

    The recent and projected increases in climate variability and the frequency of climate extremes are posing a profound challenge to society and the biosphere (IPCC 2012, IPCC 2013). Climate extremes can affect natural and managed ecosystems more severely than gradual warming. The ability of ecosystems to resist and recover from climate extremes is therefore of fundamental importance for society, which strongly relies on their ability to supply provisioning, regulating, supporting and cultural services. Society in turn triggers land-use and management decisions that affect ecosystem properties. Thus, ecological and socio-economic conditions are tightly coupled in what has been referred to as the social-ecological system. For ensuring human well-being in the light of climate extremes it is crucial to enhance the resilience of the social-ecological system (SES) across spatial, temporal and institutional scales. Stakeholders, such as resource managers, urban, landscape and conservation planners, decision-makers in agriculture and forestry, as well as natural hazards managers, require an improved knowledge base for better-informed decision making. To date the vulnerability and adaptive capacity of SESs to climate extremes is not well understood and large uncertainties exist as to the legacies of climate extremes on ecosystems and on related societal structures and processes. Moreover, we lack empirical evidence and incorporation of simulated future ecosystem and societal responses to support pro-active management and enhance social-ecological resilience. In our presentation, we outline the major research gaps and challenges to be addressed for understanding and enhancing the adaptive capacity of SES to absorb and adapt to climate extremes, including acquisition and elaboration of long-term monitoring data and improvement of ecological models to better project climate extreme effects and provide model uncertainties. We highlight scientific challenges and discuss

  3. Urbanization, Extreme Events, and Health: The Case for Systems Approaches in Mitigation, Management, and Response.

    PubMed

    Siri, José Gabriel; Newell, Barry; Proust, Katrina; Capon, Anthony

    2016-03-01

    Extreme events, both natural and anthropogenic, increasingly affect cities in terms of economic losses and impacts on health and well-being. Most people now live in cities, and Asian cities, in particular, are experiencing growth on unprecedented scales. Meanwhile, the economic and health consequences of climate-related events are worsening, a trend projected to continue. Urbanization, climate change and other geophysical and social forces interact with urban systems in ways that give rise to complex and in many cases synergistic relationships. Such effects may be mediated by location, scale, density, or connectivity, and also involve feedbacks and cascading outcomes. In this context, traditional, siloed, reductionist approaches to understanding and dealing with extreme events are unlikely to be adequate. Systems approaches to mitigation, management and response for extreme events offer a more effective way forward. Well-managed urban systems can decrease risk and increase resilience in the face of such events. © 2015 APJPH.

  4. Towards a General Theory of Extremes for Observables of Chaotic Dynamical Systems

    NASA Astrophysics Data System (ADS)

    Lucarini, Valerio; Faranda, Davide; Wouters, Jeroen; Kuna, Tobias

    2014-02-01

    In this paper we provide a connection between the geometrical properties of the attractor of a chaotic dynamical system and the distribution of extreme values. We show that the extremes of so-called physical observables are distributed according to the classical generalised Pareto distribution and derive explicit expressions for the scaling and the shape parameter. In particular, we derive that the shape parameter does not depend on the chosen observables, but only on the partial dimensions of the invariant measure on the stable, unstable, and neutral manifolds. The shape parameter is negative and is close to zero when high-dimensional systems are considered. This result agrees with what was derived recently using the generalized extreme value approach. Combining the results obtained using such physical observables and the properties of the extremes of distance observables, it is possible to derive estimates of the partial dimensions of the attractor along the stable and the unstable directions of the flow. Moreover, by writing the shape parameter in terms of moments of the extremes of the considered observable and by using linear response theory, we relate the sensitivity to perturbations of the shape parameter to the sensitivity of the moments, of the partial dimensions, and of the Kaplan-Yorke dimension of the attractor. Preliminary numerical investigations provide encouraging results on the applicability of the theory presented here. The results presented here do not apply for all combinations of Axiom A systems and observables, but the breakdown seems to be related to very special geometrical configurations.

  5. Infrared and Terahertz Spectroscopy of Strongly Correlated Electron Systems under Extreme Conditions

    NASA Astrophysics Data System (ADS)

    Kimura, Shin-ichi; Okamura, Hidekazu

    2013-02-01

    Owing to its high brilliance, infrared and terahertz synchrotron radiation (IR/THz-SR) has emerged as a powerful tool for spectroscopy under extreme (i.e., technically more difficult) experimental conditions such as high pressure, high magnetic field, high spatial resolution, and a combination of these. The methodologies for pressure- and magnetic-field-dependent spectroscopy and microscopy using IR/THz-SR have advanced rapidly worldwide. By applying them to strongly correlated electron systems (SCESs), many experimental studies have been performed on their electronic structures and phonon/molecular vibration modes under extreme conditions. Here, we review the recent progress of methodologies of IR/THz-SR spectroscopy and microscopy, and the experimental results on SCESs and other systems obtained under extreme conditions.

  6. Facilitating Co-Design for Extreme-Scale Systems Through Lightweight Simulation

    SciTech Connect

    Engelmann, Christian; Lauer, Frank

    2010-01-01

    This work focuses on tools for investigating algorithm performance at extreme scale with millions of concurrent threads and for evaluating the impact of future architecture choices to facilitate the co-design of high-performance computing (HPC) architectures and applications. The approach focuses on lightweight simulation of extreme-scale HPC systems with the needed amount of accuracy. The prototype presented in this paper is able to provide this capability using a parallel discrete event simulation (PDES), such that a Message Passing Interface (MPI) application can be executed at extreme scale, and its performance properties can be evaluated. The results of an initial prototype are encouraging as a simple 'hello world' MPI program could be scaled up to 1,048,576 virtual MPI processes on a four-node cluster, and the performance properties of two MPI programs could be evaluated at up to 16,384 virtual MPI processes on the same system.

  7. Monte Carlo-derived TLD cross-calibration factors for treatment verification and measurement of skin dose in accelerated partial breast irradiation.

    PubMed

    Garnica-Garza, H M

    2009-03-21

    Monte Carlo simulation was employed to calculate the response of TLD-100 chips under irradiation conditions such as those found during accelerated partial breast irradiation with the MammoSite radiation therapy system. The absorbed dose versus radius in the last 0.5 cm of the treated volume was also calculated, employing a resolution of 20 microm, and a function that fits the observed data was determined. Several clinically relevant irradiation conditions were simulated for different combinations of balloon size, balloon-to-surface distance and contents of the contrast solution used to fill the balloon. The thermoluminescent dosemeter (TLD) cross-calibration factors were derived assuming that the calibration of the dosemeters was carried out using a Cobalt 60 beam, and in such a way that they provide a set of parameters that reproduce the function that describes the behavior of the absorbed dose versus radius curve. Such factors may also prove to be useful for those standardized laboratories that provide postal dosimetry services.

  8. MCNP SIMULATION OF THE HP(10) ENERGY RESPONSE OF A BRAZILIAN TLD ALBEDO NEUTRON INDIVIDUAL DOSEMETER, FROM THERMAL TO 20 MeV.

    PubMed

    Freitas, B M; Martins, M M; Pereira, W W; da Silva, A X; Mauricio, C L P

    2016-09-01

    The Brazilian Instituto de Radioproteção e Dosimetria (IRD) runs a neutron individual monitoring system with a home-made TLD albedo dosemeter. It has already been characterised and calibrated in some reference fields. However, the complete energy response of this dosemeter is not known, and the calibration factors for all monitored workplace neutron fields are difficult to be obtained experimentally. Therefore, to overcome such difficulties, Monte Carlo simulations have been used. This paper describes the simulation of the HP(10) neutron response of the IRD TLD albedo dosemeter using the MCNPX transport code, for energies from thermal to 20 MeV. The validation of the MCNPX modelling is done comparing the simulated results with the experimental measurements for ISO standard neutron fields of (241)Am-Be, (252)Cf, (241)Am-B and (252)Cf(D2O) and also for (241)Am-Be source moderated with paraffin and silicone. Bare (252)Cf are used for normalisation.

  9. Design and optimization of a dedicated cone-beam CT system for musculoskeletal extremities imaging

    NASA Astrophysics Data System (ADS)

    Zbijewski, W.; De Jean, P.; Prakash, P.; Ding, Y.; Stayman, J. W.; Packard, N.; Senn, R.; Yang, D.; Yorkston, J.; Machado, A.; Carrino, J. A.; Siewerdsen, J. H.

    2011-03-01

    The design, initial imaging performance, and model-based optimization of a dedicated cone-beam CT (CBCT) scanner for musculoskeletal extremities is presented. The system offers a compact scanner that complements conventional CT and MR by providing sub-mm isotropic spatial resolution, the ability to image weight-bearing extremities, and the capability for integrated real-time fluoroscopy and digital radiography. The scanner employs a flat-panel detector and a fixed anode x-ray source and has a field of view of ~ (20x20x20) cm3. The gantry allows a "standing" configuration for imaging of weight-bearing lower extremities and a "sitting" configuration for imaging of upper extremities and unloaded lower extremities. Cascaded systems analysis guided the selection of x-ray technique (e.g., kVp, filtration, and dose) and system design (e.g., magnification factor), yielding input-quantum-limited performance at detector signal of 100 times the electronic noise, while maintaining patient dose below 5 mGy (a factor of ~2-3 less than conventional CT). A magnification of 1.3 optimized tradeoffs between source and detector blur for a 0.5 mm focal spot. A custom antiscatter grid demonstrated significant reduction of artifacts without loss of contrast-to-noise ratio or increase in dose. Image quality in cadaveric specimens was assessed on a CBCT bench, demonstrating exquisite bone detail, visualization of intra-articular morphology, and soft-tissue visibility approaching that of diagnostic CT. The capability to image loaded extremities and conduct multi-modality CBCT/fluoroscopy with improved workflow compared to whole-body CT could be of value in a broad spectrum of applications, including orthopaedics, rheumatology, surgical planning, and treatment assessment. A clinical prototype has been constructed for deployment in pilot study trials.

  10. On data-based analysis of extreme events in multidimensional non-stationary meteorological systems: Based on advanced time series analysis methods and general extreme value theory

    NASA Astrophysics Data System (ADS)

    Kaiser, O.; Horenko, I.

    2012-04-01

    Given an observed series of extreme events we are interested to capture the significant trend in the underlying dynamics. Since the character of such systems is strongly non-linear and non-stationary, the detection of significant characteristics and their attribution is a complex task. A standard tool in statistics to describe the probability distribution of extreme events is the General Extreme Value Theory (GEV). While the univariate stationary GEV distribution is well studied and results in fitting the data to the model parameters using Likelihood Techniques and Bayesian Methods (Coles,'01; Davison, Rames, '00 ), analysis of non-stationary extremes is based on the a priori assumption about the trend behavior (e.g linear combination of external factors/polynomials (Coles,'01)). Additionally, analysis of multivariate, non-stationary extreme events remains still a strong challenge, since analysis without strong a priori assumptions is limited to low dimensional cases (Nychka, Cooley,'09). We introduce FEM-GEV approach, which is based on GEV and advanced Finite Element time series analysis Methods (FEM) (Horenko,'10-11). The main idea of the FEM framework is to interpolate adaptively the corresponding non-stationary model parameters by a linear convex combination of K local stationary models and a switching process between them. To apply FEM framework to a time series of extremes we extend FEM by defining the model parameters wrt GEV distribution, as external factors we consider global atmospheric patterns. The optimal number of local models K and the best combination of external factors is estimated using Akaike Information Criteria. FEM-GEV approach allows to study the non-stationary dynamics of GEV parameters without a priori assumptions on the trend behavior and also captures the non-linear, non-stationary dependence on external factors. The series of extremes has by definition no connection to real time scale, for this reason the results of FEM-GEV can be only

  11. New Extreme Trans-Neptunian Objects: Toward a Super-Earth in the Outer Solar System

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott S.; Trujillo, Chadwick

    2016-12-01

    We are performing a wide and deep survey for extreme distant solar system objects. Our goal is to understand the high-perihelion objects Sedna and 2012 VP113 and determine if an unknown massive planet exists in the outer solar system. The discovery of new extreme objects from our survey of some 1080 square degrees of sky to over 24th magnitude in the r-band are reported. Two of the new objects, 2014 SR349 and 2013 FT28, are extreme detached trans-Neptunian objects, which have semimajor axes greater than 150 au and perihelia well beyond Neptune (q > 40 au). Both new objects have orbits with arguments of perihelia within the range of the clustering of this angle seen in the other known extreme objects. One of these objects, 2014 SR349, has a longitude of perihelion similar to the other extreme objects, but 2013 FT28 is about 180° away or anti-aligned in its longitude of perihelion. We also discovered the first outer Oort Cloud object with a perihelion beyond Neptune, 2014 FE72. We discuss these and other interesting objects discovered in our ongoing survey. All the high semimajor axis (a > 150 au) and high-perihelion (q > 35 au) bodies follow the previously identified argument of perihelion clustering as first reported and explained as being from an unknown massive planet in 2014 by Trujillo & Sheppard, which some have called Planet X or Planet Nine. With the discovery of 2013 FT28 on the opposite side of the sky, we now report that the argument of perihelion is significantly correlated with the longitude of perihelion and orbit pole angles for extreme objects and find there are two distinct extreme clusterings anti-aligned with each other. This previously unnoticed correlation is further evidence of an unknown massive planet on a distant eccentric inclined orbit, as extreme eccentric objects with perihelia on opposite sides of the sky (180° longitude of perihelion differences) would approach the inclined planet at opposite points in their orbits, thus making the

  12. Extreme weather events: Should drinking water quality management systems adapt to changing risk profiles?

    PubMed

    Khan, Stuart J; Deere, Daniel; Leusch, Frederic D L; Humpage, Andrew; Jenkins, Madeleine; Cunliffe, David

    2015-11-15

    Among the most widely predicted and accepted consequences of global climate change are increases in both the frequency and severity of a variety of extreme weather events. Such weather events include heavy rainfall and floods, cyclones, droughts, heatwaves, extreme cold, and wildfires, each of which can potentially impact drinking water quality by affecting water catchments, storage reservoirs, the performance of water treatment processes or the integrity of distribution systems. Drinking water guidelines, such as the Australian Drinking Water Guidelines and the World Health Organization Guidelines for Drinking-water Quality, provide guidance for the safe management of drinking water. These documents present principles and strategies for managing risks that may be posed to drinking water quality. While these principles and strategies are applicable to all types of water quality risks, very little specific attention has been paid to the management of extreme weather events. We present a review of recent literature on water quality impacts of extreme weather events and consider practical opportunities for improved guidance for water managers. We conclude that there is a case for an enhanced focus on the management of water quality impacts from extreme weather events in future revisions of water quality guidance documents. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Development of a Wafer Positioning System for the Sandia Extreme Ultraviolet Lithography Tool

    NASA Technical Reports Server (NTRS)

    Wronosky, John B.; Smith, Tony G.; Darnold, Joel R.

    1996-01-01

    A wafer positioning system was recently developed by Sandia National Laboratories for an Extreme Ultraviolet Lithography (EUVL) tool. The system, which utilizes a magnetically levitated fine stage to provide ultra-precise positioning in all six degrees of freedom, incorporates technological improvements resulting from four years of prototype development. This paper describes the design, implementation, and functional capability of the system. Specifics regarding control system electronics, including software and control algorithm structure, as well as performance design goals and test results are presented. Potential system enhancements, some of which are in process, are also discussed.

  14. Development of a wafer positioning system for the Sandia extreme ultraviolet lithography tool

    SciTech Connect

    Wronosky, J.B.; Smith, T.G.; Darnold, J.R.

    1995-12-01

    A wafer positioning system was recently developed by Sandia National Laboratories for an Extreme Ultraviolet Lithography (EUVL) tool. The system, which utilizes a magnetically levitated fine stage to provide ultra-precise positioning in all six degrees of freedom, incorporates technological improvements resulting from four years of prototype development. This paper describes the design, implementation, and functional capability of the system. Specifics regarding control system electronics, including software and control algorithm structure, as well as performance design goals and test results are presented. Potential system enhancements, some of which are in process, are also discussed.

  15. Microwave tomography of extremities: 1) Dedicated 2D system and physiological signatures

    PubMed Central

    Semenov, Serguei; Kellam, James; Sizov, Yuri; Nazarov, Alexei; Williams, Thomas; Nair, Bindu; Pavlovsky, Andrey; Posukh, Vitaly; Quinn, Michael

    2011-01-01

    Microwave Tomography (MWT) is a novel imaging modality which might be applicable for non-invasive assessment of functional and pathological conditions of biological tissues. The imaging of the soft tissue of extremities is one of its potential applications. The feasibility of this technology for such applications was demonstrated earlier. This is the first of two companion papers focused on an application of MWT for imaging of the extremity’s soft tissues. The goal of this study is to assess the technical performance of the developed 2D MWT system dedicated for imaging of functional and pathological conditions of the extremity’s soft tissues. Specifically, the system’s performance was tested by its ability to detect signals associated with physiological activity and soft tissue interventions (circulatory related changes, blood flow reduction and a simulated compartmental syndrome) – so called “physiological signatures”. The developed 2D MWT system dedicated for an imaging of animal extremities demonstrates good technical performance allowing for stable and predictable data acquisition with reasonable agreement between experimentally measured electromagnetic (EM) field and simulated EM field within a measurement domain. Using the system we were able to obtain physiological signatures associated with systolic vs diastolic phases of circulation in an animal extremity, reperfusion vs occlusion phases of the blood supply to the animal’s extremity and the a compartment syndrome. The imaging results are presented and discussed in the second companion paper. PMID:21364265

  16. Co-Alignment System (CAS) study. Report on task 1-3. [Solar Extreme Ultraviolet Telescope and Spectrometer pointing system

    NASA Technical Reports Server (NTRS)

    Anderson, N. T.

    1980-01-01

    The design of a suitable coalignment system (CAS) for the Solar Extreme Ultraviolet Telescope and Spectrometer (SEUTS) is presented. The CAS provides offset adjustment capabilities to SEUTS which will be mounted on a single large pointing system with other devices. The suitability of existing designs is determined and modifications are suggested.

  17. VALIDATION OF HANFORD PERSONNEL AND EXTREMITY DOSIMETERS IN PLUTONIUM ENVIRONMENTS

    SciTech Connect

    Scherpelz, Robert I.; Fix, John J.; Rathbone, Bruce A.

    2000-02-10

    A study was performed in the Plutonium Finishing Plant to assess the performance of Hanford personnel neutron dosimetry. The study was assessed whole body dosimetry and extremity dosimetry performance. For both parts of the study, the TEPC was used as the principle instrument for characterizing workplace neutron fields. In the whole body study, 12.7-cm-diameter TEPCs were used in ten different locations in the facility. TLD and TED personnel dosimeters were exposed on a water-filled phantom to enable a comparison of TEPC and dosimeter response. In the extremity study, 1.27-cm-diameter TEPCs were exposed inside the fingers of a gloveboxe glove. Extremity dosimeters were wrapped around the TEPCs. The glove was then exposed to six different cans of plutonium, simulating the exposure that a worker's fingers would receive in a glovebox. The comparison of TEPC-measured neutron dose equivalent to TLD-measured gamma dose equivalent provided neutron-to-gamma ratios that can be used to estimate the neutron dose equivalent received by a worker's finger based on the gamma readings of an extremity dosimeter. The study also utilized a Snoopy and detectors based on bubble technology for assessing neutron exposures, providing a comparison of the effectiveness of these instruments for workplace monitoring. The study concludes that the TLD component of the HCND performs adequately overall, with a positive bias of 30%, but exhibits excessive variability in individual results due to instabilities in the algorithm. The TED response was less variable but only 20% of the TEPC reference dose on average because of the low neutron energies involved. The neutron response of the HSD was more variable than the TLD component of the HCND and biased high by a factor of 8 overall due to its calibration to unmoderated 252Cf. The study recommends further work to correct instabilities in the HCND algorithm and to explore the potential shown by the bubble-based dosimeters.

  18. Variations in photon energy spectra of a 6 MV beam and their impact on TLD response

    PubMed Central

    Scarboro, Sarah B.; Followill, David S.; Howell, Rebecca M.; Kry, Stephen F.

    2011-01-01

    Purpose: Measurement of the absorbed dose from radiotherapy beams is an essential component of providing safe and reproducible treatment. For an energy-dependent dosimeter such as thermoluminescent dosimeters (TLDs), it is generally assumed that the energy spectrum is constant throughout the treatment field and is unperturbed by field size, depth, field modulation, or heterogeneities. However, this does not reflect reality and introduces error into clinical dose measurements. The purpose of this study was to evaluate the variability in the energy spectrum of a Varian 6 MV beam and to evaluate the impact of these variations in photon energy spectra on the response of a common energy-dependent dosimeter, TLD. Methods: Using Monte Carlo methods, we calculated variations in the photon energy spectra of a 6 MV beam as a result of variations of treatment parameters, including field size, measurement location, the presence of heterogeneities, and field modulation. The impact of these spectral variations on the response of the TLD is largely based on increased photoelectric effect in the dosimeter, and this impact was calculated using Burlin cavity theory. Measurements of the energy response were also made to determine the additional energy response due to all intrinsic and secondary effects. Results: For most in-field measurements, regardless of treatment parameter, the dosimeter response was not significantly affected by the spectral variations (<1% effect). For measurement points outside of the treatment field, where the spectrum is softer, the TLD over-responded by up to 12% due to an increased probability of photoelectric effect in the TLD material as well as inherent ionization density effects that play a role at low photon energies. Conclusions: It is generally acceptable to ignore the impact of variations in the photon spectrum on the measured dose for locations within the treatment field. However, outside the treatment field, the spectra are much softer, and a

  19. Monitoring of Occupational Exposures in Albania Using TLD-100 cards (2003-2007)

    NASA Astrophysics Data System (ADS)

    Qafmolla, Luan; Hoxhaj, Enver

    2010-01-01

    In our paper is described the monitoring of occupational staff that works in ionising radiation field of the diagnostic centres in Albania for 2003-2007, and is analysed and discussed the mean annual dose rate recorded for above-mentioned period. The monitoring was based in TLD-100 dosimetric cards and the control was performed all over the country on bimonthly basis covering main and important cities like: Tirana, Durresi, Shkodra, Fieri, Vlora, Korça etj. The Department of Human & Environment Protection, at the Centre of Applied Nuclear Physics, through the dosimetric service carried out the monitoring for around 350 radiation workers.

  20. Monitoring of Occupational Exposures in Albania Using TLD-100 cards (2003-2007)

    SciTech Connect

    Qafmolla, Luan; Hoxhaj, Enver

    2010-01-21

    In our paper is described the monitoring of occupational staff that works in ionising radiation field of the diagnostic centres in Albania for 2003-2007, and is analysed and discussed the mean annual dose rate recorded for above-mentioned period. The monitoring was based in TLD-100 dosimetric cards and the control was performed all over the country on bimonthly basis covering main and important cities like: Tirana, Durresi, Shkodra, Fieri, Vlora, Korca etj. The Department of Human and Environment Protection, at the Centre of Applied Nuclear Physics, through the dosimetric service carried out the monitoring for around 350 radiation workers.

  1. Reliability of a Scoring System for Qualitative Evaluation of Lymphoscintigraphy of the Lower Extremities.

    PubMed

    Ebrahim, Mojgan; Savitcheva, Irina; Axelsson, Rimma

    2017-09-01

    Lymphoscintigraphy is an imaging technique to diagnose and characterize the severity of edema in the upper and lower extremities. In lymphoscintigraphy, a scoring system can increase the ability to differentiate between diagnoses, but the use of any scoring system requires sufficient reliability. Our aim was to determine the inter- and intraobserver reliability of a proposed scoring system for visual interpretation of lymphoscintigrams of the lower extremities. Methods: The lymphoscintigrams of 81 persons were randomly selected from our database for retrospective evaluation. Two nuclear medicine physicians scored these scans according to the 8 criteria of a proposed scoring system for visual interpretation of lymphoscintigrams of the lower extremities. Each scan was scored twice 3 mo apart. The total score was the sum of the scores for all criteria, with a potential range of 0 (normal lymphatic drainage) to 58 (severe lymphatic impairment). The intra- and interobserver reliability of the scoring system was determined using the Wilcoxon signed-rank test, percentage of agreement, weighted κ, and intraclass correlation coefficient with 95% confidence interval. In addition, for 7 categories, differences in total scores between and within observers were determined. Results: We found some insignificant differences between observers. Percentage agreement was high or very high, at 82.7%-99.4% between observers and 84.6%-99.4% within observers. For each criterion of the scoring system, the κ-correlations showed moderate to very good inter- or intraobserver reliability. The total scores for all criteria had good inter- and intraobserver reliability. Regarding the interobserver comparison, 66% and 64% of the difference in total scores were within ±1 scale point (-1, +1), and regarding the intraobserver comparison, 68% and 72% of the difference in total scores were within ±1 scale point. Conclusion: The proposed scoring system is a reliable tool for visual qualitative

  2. SAXO: the extreme adaptive optics system of SPHERE (I) system overview and global laboratory performance

    NASA Astrophysics Data System (ADS)

    Sauvage, Jean-Francois; Fusco, Thierry; Petit, Cyril; Costille, Anne; Mouillet, David; Beuzit, Jean-Luc; Dohlen, Kjetil; Kasper, Markus; Suarez, Marcos; Soenke, Christian; Baruffolo, Andrea; Salasnich, Bernardo; Rochat, Sylvain; Fedrigo, Enrico; Baudoz, Pierre; Hugot, Emmanuel; Sevin, Arnaud; Perret, Denis; Wildi, Francois; Downing, Mark; Feautrier, Philippe; Puget, Pascal; Vigan, Arthur; O'Neal, Jared; Girard, Julien; Mawet, Dimitri; Schmid, Hans Martin; Roelfsema, Ronald

    2016-04-01

    The direct imaging of exoplanet is a leading field of today's astronomy. The photons coming from the planet carry precious information on the chemical composition of its atmosphere. The second-generation instrument, Spectro-Polarimetric High contrast Exoplanet Research (SPHERE), dedicated to detection, photometry and spectral characterization of Jovian-like planets, is now in operation on the European very large telescope. This instrument relies on an extreme adaptive optics (XAO) system to compensate for atmospheric turbulence as well as for internal errors with an unprecedented accuracy. We demonstrate the high level of performance reached by the SPHERE XAO system (SAXO) during the assembly integration and test (AIT) period. In order to fully characterize the instrument quality, two AIT periods have been mandatory. In the first phase at Observatoire de Paris, the performance of SAXO itself was assessed. In the second phase at IPAG Grenoble Observatory, the operation of SAXO in interaction with the overall instrument has been optimized. In addition to the first two phases, a final check has been performed after the reintegration of the instrument at Paranal Observatory, in the New Integration Hall before integration at the telescope focus. The final performance aimed by the SPHERE instrument with the help of SAXO is among the highest Strehl ratio pretended for an operational instrument (90% in H band, 43% in V band in a realistic turbulence r0, and wind speed condition), a limit R magnitude for loop closure at 15, and a robustness to high wind speeds. The full-width at half-maximum reached by the instrument is 40 mas for infrared in H band and unprecedented 18.5 mas in V band.

  3. The response of the soil microbial food web to extreme rainfall under different plant systems

    NASA Astrophysics Data System (ADS)

    Sun, Feng; Pan, Kaiwen; Tariq, Akash; Zhang, Lin; Sun, Xiaoming; Li, Zilong; Wang, Sizhong; Xiong, Qinli; Song, Dagang; Olatunji, Olusanya Abiodun

    2016-11-01

    An agroforestry experiment was conducted that involved four planting systems: monoculture of the focal species Zanthoxylum bungeanum and mixed cultures of Z. bungeanum and Capsicum annuum, Z. bungeanum and Medicago sativa and Z. bungeanum and Glycine max. Soil microbial food web (microorganisms and nematodes) was investigated under manipulated extreme rainfall in the four planting systems to assess whether presence of neighbor species alleviated the magnitude of extreme rainfall on nutrient uptake of the focal species by increasing the stability of soil food web. Our results indicate that in the focal species and G. max mixed culture, leaf nitrogen contents of the focal species were higher than in the monoculture and in the other mixed cultures under extreme rainfall. This result was mainly due to the significant increase under extreme rainfall of G. max species root biomass, resulting in enhanced microbial resistance and subsequent net nitrogen mineralization rate and leaf nitrogen uptake for the focal species. Differences in functional traits of neighbors had additive effects and led to a marked divergence of soil food-web resistance and nutrient uptake of the focal species. Climate change can indirectly alleviate focal species via its influence on their neighbors.

  4. The response of the soil microbial food web to extreme rainfall under different plant systems

    PubMed Central

    Sun, Feng; Pan, Kaiwen; Tariq, Akash; Zhang, Lin; Sun, Xiaoming; Li, Zilong; Wang, Sizhong; Xiong, Qinli; Song, Dagang; Olatunji, Olusanya Abiodun

    2016-01-01

    An agroforestry experiment was conducted that involved four planting systems: monoculture of the focal species Zanthoxylum bungeanum and mixed cultures of Z. bungeanum and Capsicum annuum, Z. bungeanum and Medicago sativa and Z. bungeanum and Glycine max. Soil microbial food web (microorganisms and nematodes) was investigated under manipulated extreme rainfall in the four planting systems to assess whether presence of neighbor species alleviated the magnitude of extreme rainfall on nutrient uptake of the focal species by increasing the stability of soil food web. Our results indicate that in the focal species and G. max mixed culture, leaf nitrogen contents of the focal species were higher than in the monoculture and in the other mixed cultures under extreme rainfall. This result was mainly due to the significant increase under extreme rainfall of G. max species root biomass, resulting in enhanced microbial resistance and subsequent net nitrogen mineralization rate and leaf nitrogen uptake for the focal species. Differences in functional traits of neighbors had additive effects and led to a marked divergence of soil food-web resistance and nutrient uptake of the focal species. Climate change can indirectly alleviate focal species via its influence on their neighbors. PMID:27874081

  5. Extreme temperature trends in major cropping systems and their relation to agricultural land use change

    NASA Astrophysics Data System (ADS)

    Mueller, N. D.; Butler, E. E.; McKinnon, K. A.; Rhines, A. N.; Tingley, M.; Siebert, S.; Holbrook, N. M.; Huybers, P. J.

    2015-12-01

    High temperature extremes during the growing season can reduce agricultural production. At the same time, agricultural practices can modify temperatures by altering the surface energy budget. Here we investigate growing season climate trends in major cropping systems and their relationship with agricultural land use change. In the US Midwest, 100-year trends exhibit a transition towards more favorable conditions, with cooler summer temperature extremes and increased precipitation. Statistically significant correspondence is found between the cooling pattern and trends in cropland intensification, as well as with trends towards greater irrigated land over a small subset of the domain. Land conversion to cropland, often considered an important influence on historical temperatures, is not significantly associated with cooling. We suggest that cooling is primarily associated with agricultural intensification increasing the potential for evapotranspiration, consistent with our finding that cooling trends are greatest for the highest temperature percentiles, and that increased evapotranspiration generally leads to greater precipitation. Temperatures over rainfed croplands show no cooling trend during drought conditions, consistent with evapotranspiration requiring adequate soil moisture, and implying that modern drought events feature greater warming as baseline cooler temperatures revert to historically high extremes. Preliminary results indicate these relationships between temperature extremes, irrigation, and intensification are also observed in other major summer cropping systems, including northeast China, Argentina, and the Canadian Prairies.

  6. An extra-uterine system to physiologically support the extreme premature lamb.

    PubMed

    Partridge, Emily A; Davey, Marcus G; Hornick, Matthew A; McGovern, Patrick E; Mejaddam, Ali Y; Vrecenak, Jesse D; Mesas-Burgos, Carmen; Olive, Aliza; Caskey, Robert C; Weiland, Theodore R; Han, Jiancheng; Schupper, Alexander J; Connelly, James T; Dysart, Kevin C; Rychik, Jack; Hedrick, Holly L; Peranteau, William H; Flake, Alan W

    2017-04-25

    In the developed world, extreme prematurity is the leading cause of neonatal mortality and morbidity due to a combination of organ immaturity and iatrogenic injury. Until now, efforts to extend gestation using extracorporeal systems have achieved limited success. Here we report the development of a system that incorporates a pumpless oxygenator circuit connected to the fetus of a lamb via an umbilical cord interface that is maintained within a closed 'amniotic fluid' circuit that closely reproduces the environment of the womb. We show that fetal lambs that are developmentally equivalent to the extreme premature human infant can be physiologically supported in this extra-uterine device for up to 4 weeks. Lambs on support maintain stable haemodynamics, have normal blood gas and oxygenation parameters and maintain patency of the fetal circulation. With appropriate nutritional support, lambs on the system demonstrate normal somatic growth, lung maturation and brain growth and myelination.

  7. An extra-uterine system to physiologically support the extreme premature lamb

    PubMed Central

    Partridge, Emily A.; Davey, Marcus G.; Hornick, Matthew A.; McGovern, Patrick E.; Mejaddam, Ali Y.; Vrecenak, Jesse D.; Mesas-Burgos, Carmen; Olive, Aliza; Caskey, Robert C.; Weiland, Theodore R.; Han, Jiancheng; Schupper, Alexander J.; Connelly, James T.; Dysart, Kevin C.; Rychik, Jack; Hedrick, Holly L.; Peranteau, William H.; Flake, Alan W.

    2017-01-01

    In the developed world, extreme prematurity is the leading cause of neonatal mortality and morbidity due to a combination of organ immaturity and iatrogenic injury. Until now, efforts to extend gestation using extracorporeal systems have achieved limited success. Here we report the development of a system that incorporates a pumpless oxygenator circuit connected to the fetus of a lamb via an umbilical cord interface that is maintained within a closed ‘amniotic fluid' circuit that closely reproduces the environment of the womb. We show that fetal lambs that are developmentally equivalent to the extreme premature human infant can be physiologically supported in this extra-uterine device for up to 4 weeks. Lambs on support maintain stable haemodynamics, have normal blood gas and oxygenation parameters and maintain patency of the fetal circulation. With appropriate nutritional support, lambs on the system demonstrate normal somatic growth, lung maturation and brain growth and myelination. PMID:28440792

  8. An extra-uterine system to physiologically support the extreme premature lamb

    NASA Astrophysics Data System (ADS)

    Partridge, Emily A.; Davey, Marcus G.; Hornick, Matthew A.; McGovern, Patrick E.; Mejaddam, Ali Y.; Vrecenak, Jesse D.; Mesas-Burgos, Carmen; Olive, Aliza; Caskey, Robert C.; Weiland, Theodore R.; Han, Jiancheng; Schupper, Alexander J.; Connelly, James T.; Dysart, Kevin C.; Rychik, Jack; Hedrick, Holly L.; Peranteau, William H.; Flake, Alan W.

    2017-04-01

    In the developed world, extreme prematurity is the leading cause of neonatal mortality and morbidity due to a combination of organ immaturity and iatrogenic injury. Until now, efforts to extend gestation using extracorporeal systems have achieved limited success. Here we report the development of a system that incorporates a pumpless oxygenator circuit connected to the fetus of a lamb via an umbilical cord interface that is maintained within a closed `amniotic fluid' circuit that closely reproduces the environment of the womb. We show that fetal lambs that are developmentally equivalent to the extreme premature human infant can be physiologically supported in this extra-uterine device for up to 4 weeks. Lambs on support maintain stable haemodynamics, have normal blood gas and oxygenation parameters and maintain patency of the fetal circulation. With appropriate nutritional support, lambs on the system demonstrate normal somatic growth, lung maturation and brain growth and myelination.

  9. Critical evaluation of mangled extremity severity scoring system in Indian patients.

    PubMed

    Sharma, Sansar; Devgan, Ashish; Marya, K M; Rathee, Nitesh

    2003-07-01

    Amputation of a mangled extremity is repugnant to the patient and the surgeon. However, prolonged unsuccessful attempts at salvage are costly, highly morbid and sometimes lethal. Much discussion has taken place regarding which criteria predict successful salvage, and predictive indices have been proposed in an attempt to identify limbs for which attempted salvage is unlikely to succeed. The mangled extremity severity score, or MESS system is the most thoroughly validated of the various classification systems, but at present there is no predictive scale that can be used with confidence to determine whether to amputate or attempt to salvage a mangled lower extremity. MESS system based on four significant criteria (with increasing points with worsening prognosis) i.e. skeletal injury, limb ischaemia, shock and patient age, has become a standard method to determine which one of the mangled extremities will eventually undergo amputation or salvage. Keeping in view the paucity of studies on Indian patients, a prospective trial of MESS was done in 50 patients who had 56 mangled extremities during the last 3 years. A significant difference between the MESS value of salvaged limbs (4.7) and amputated limbs (8.6) was found. MESS value of more than 7 was most specific and was found to have a positive predictive value of 100%. The results have been compared with Western literature and authors suggest that nerve injuries and irreparable soft tissue loss should be given an extra point each. In bilateral cases, the MESS value of each limb should be properly assessed (especially when patient is in shock), as the score may increase because of the other injured limb.

  10. Improving the Statistical Modeling of the TRMM Extreme Precipitation Monitoring System

    NASA Astrophysics Data System (ADS)

    Demirdjian, L.; Zhou, Y.; Huffman, G. J.

    2016-12-01

    This project improves upon an existing extreme precipitation monitoring system based on the Tropical Rainfall Measuring Mission (TRMM) daily product (3B42) using new statistical models. The proposed system utilizes a regional modeling approach, where data from similar grid locations are pooled to increase the quality and stability of the resulting model parameter estimates to compensate for the short data record. The regional frequency analysis is divided into two stages. In the first stage, the region defined by the TRMM measurements is partitioned into approximately 27,000 non-overlapping clusters using a recursive k-means clustering scheme. In the second stage, a statistical model is used to characterize the extreme precipitation events occurring in each cluster. Instead of utilizing the block-maxima approach used in the existing system, where annual maxima are fit to the Generalized Extreme Value (GEV) probability distribution at each cluster separately, the present work adopts the peak-over-threshold (POT) method of classifying points as extreme if they exceed a pre-specified threshold. Theoretical considerations motivate the use of the Generalized-Pareto (GP) distribution for fitting threshold exceedances. The fitted parameters can be used to construct simple and intuitive average recurrence interval (ARI) maps which reveal how rare a particular precipitation event is given its spatial location. The new methodology eliminates much of the random noise that was produced by the existing models due to a short data record, producing more reasonable ARI maps when compared with NOAA's long-term Climate Prediction Center (CPC) ground based observations. The resulting ARI maps can be useful for disaster preparation, warning, and management, as well as increased public awareness of the severity of precipitation events. Furthermore, the proposed methodology can be applied to various other extreme climate records.

  11. Analysis of read-out heating rate effects on the glow peaks of TLD-100 using WinGCF software

    SciTech Connect

    Bauk, Sabar; Hussin, Siti Fatimah; Alam, Md. Shah

    2016-01-22

    This study was done to analyze the effects of the read-out heating rate on the LiF:Mg,Ti (TLD-100) thermoluminescent dosimeters (TLD) glow peaks using WinGCF computer software. The TLDs were exposed to X-ray photons with a potential difference of 72 kVp and 200 mAs in air and were read-out using a Harshaw 3500 TLD reader. The TLDs were read-out using four read-out heating rates at 10, 7, 4 and 1 °C s{sup −1}. It was observed that lowering the heating rate could separate more glow peaks. The activation energy for peak 5 was found to be lower than that for peak 4. The peak maximum temperature and the integral value of the main peak decreased as the heating rate decreases.

  12. Multiplex APLP System for High-Resolution Haplogrouping of Extremely Degraded East-Asian Mitochondrial DNAs

    PubMed Central

    Kakuda, Tsuneo; Shojo, Hideki; Tanaka, Mayumi; Nambiar, Phrabhakaran; Minaguchi, Kiyoshi; Umetsu, Kazuo; Adachi, Noboru

    2016-01-01

    Mitochondrial DNA (mtDNA) serves as a powerful tool for exploring matrilineal phylogeographic ancestry, as well as for analyzing highly degraded samples, because of its polymorphic nature and high copy numbers per cell. The recent advent of complete mitochondrial genome sequencing has led to improved techniques for phylogenetic analyses based on mtDNA, and many multiplex genotyping methods have been developed for the hierarchical analysis of phylogenetically important mutations. However, few high-resolution multiplex genotyping systems for analyzing East-Asian mtDNA can be applied to extremely degraded samples. Here, we present a multiplex system for analyzing mitochondrial single nucleotide polymorphisms (mtSNPs), which relies on a novel amplified product-length polymorphisms (APLP) method that uses inosine-flapped primers and is specifically designed for the detailed haplogrouping of extremely degraded East-Asian mtDNAs. We used fourteen 6-plex polymerase chain reactions (PCRs) and subsequent electrophoresis to examine 81 haplogroup-defining SNPs and 3 insertion/deletion sites, and we were able to securely assign the studied mtDNAs to relevant haplogroups. Our system requires only 1×10−13 g (100 fg) of crude DNA to obtain a full profile. Owing to its small amplicon size (<110 bp), this new APLP system was successfully applied to extremely degraded samples for which direct sequencing of hypervariable segments using mini-primer sets was unsuccessful, and proved to be more robust than conventional APLP analysis. Thus, our new APLP system is effective for retrieving reliable data from extremely degraded East-Asian mtDNAs. PMID:27355212

  13. SU-E-T-172: Characterization of TLD-100 (LiF:Mg,Ti) Microcube Energy Response in a Cylindrical Chamber Phantom

    SciTech Connect

    Desai, V; Hammer, C; Kunugi, K; Culberson, W; DeWerd, L

    2015-06-15

    Purpose: To characterize the energy response of TLD-100 microcubes inside a Virtual Water chamber phantom. Methods: Four TLD microcubes were placed inside a water-proof Virtual Water (VW) chamber phantom and irradiated to a known dose on a Varian linac in a 1D water tank. These chamber phantoms were then replaced by TLD-100 chips inside a separate VW paddle and irradiated to the same dose. Each energy response reading was calculated as light output per unit dose in nC/cGy and normalized to a calibration set irradiated to the same dose in 60Co. The differences in response between the TLD chips and microcubes were then analyzed. Results: Across all energies, the average microcube response was less sensitive to energy than the average chip response with both falling consistently within 2.8% of previously established values in the literature Conclusion: TLD microcubes showed a lower average sensitivity to energy than their TLD chip counterparts. The use of TLD-100 microcubes inside the chamber phantom was validated against TLD-100 chips inside of VW paddles.

  14. Extreme multistability in a memristor-based multi-scroll hyper-chaotic system.

    PubMed

    Yuan, Fang; Wang, Guangyi; Wang, Xiaowei

    2016-07-01

    In this paper, a new memristor-based multi-scroll hyper-chaotic system is designed. The proposed memristor-based system possesses multiple complex dynamic behaviors compared with other chaotic systems. Various coexisting attractors and hidden coexisting attractors are observed in this system, which means extreme multistability arises. Besides, by adjusting parameters of the system, this chaotic system can perform single-scroll attractors, double-scroll attractors, and four-scroll attractors. Basic dynamic characteristics of the system are investigated, including equilibrium points and stability, bifurcation diagrams, Lyapunov exponents, and so on. In addition, the presented system is also realized by an analog circuit to confirm the correction of the numerical simulations.

  15. Extreme multistability in a memristor-based multi-scroll hyper-chaotic system

    NASA Astrophysics Data System (ADS)

    Yuan, Fang; Wang, Guangyi; Wang, Xiaowei

    2016-07-01

    In this paper, a new memristor-based multi-scroll hyper-chaotic system is designed. The proposed memristor-based system possesses multiple complex dynamic behaviors compared with other chaotic systems. Various coexisting attractors and hidden coexisting attractors are observed in this system, which means extreme multistability arises. Besides, by adjusting parameters of the system, this chaotic system can perform single-scroll attractors, double-scroll attractors, and four-scroll attractors. Basic dynamic characteristics of the system are investigated, including equilibrium points and stability, bifurcation diagrams, Lyapunov exponents, and so on. In addition, the presented system is also realized by an analog circuit to confirm the correction of the numerical simulations.

  16. Extreme multistability in a memristor-based multi-scroll hyper-chaotic system

    SciTech Connect

    Yuan, Fang Wang, Guangyi; Wang, Xiaowei

    2016-07-15

    In this paper, a new memristor-based multi-scroll hyper-chaotic system is designed. The proposed memristor-based system possesses multiple complex dynamic behaviors compared with other chaotic systems. Various coexisting attractors and hidden coexisting attractors are observed in this system, which means extreme multistability arises. Besides, by adjusting parameters of the system, this chaotic system can perform single-scroll attractors, double-scroll attractors, and four-scroll attractors. Basic dynamic characteristics of the system are investigated, including equilibrium points and stability, bifurcation diagrams, Lyapunov exponents, and so on. In addition, the presented system is also realized by an analog circuit to confirm the correction of the numerical simulations.

  17. Applying systems biology methods to the study of human physiology in extreme environments.

    PubMed

    Edwards, Lindsay M; Thiele, Ines

    2013-03-22

    Systems biology is defined in this review as 'an iterative process of computational model building and experimental model revision with the aim of understanding or simulating complex biological systems'. We propose that, in practice, systems biology rests on three pillars: computation, the omics disciplines and repeated experimental perturbation of the system of interest. The number of ethical and physiologically relevant perturbations that can be used in experiments on healthy humans is extremely limited and principally comprises exercise, nutrition, infusions (e.g. Intralipid), some drugs and altered environment. Thus, we argue that systems biology and environmental physiology are natural symbionts for those interested in a system-level understanding of human biology. However, despite excellent progress in high-altitude genetics and several proteomics studies, systems biology research into human adaptation to extreme environments is in its infancy. A brief description and overview of systems biology in its current guise is given, followed by a mini review of computational methods used for modelling biological systems. Special attention is given to high-altitude research, metabolic network reconstruction and constraint-based modelling.

  18. Functional Fatigue and Upper Extremity Sensorimotor System Acuity in Baseball Athletes

    PubMed Central

    Tripp, Brady L; Yochem, Eric M; Uhl, Timothy L

    2007-01-01

    Context: The sensorimotor system controls the balance between upper extremity stability and mobility during athletic performance. Research indicates that fatigue hampers sensorimotor system function; however, few investigators have studied functional fatigue or multijoint, multiplanar measures. Objective: To examine the effect of functional fatigue on upper extremity position reproduction in overhead throwing athletes. Design: Single-session, repeated-measures design. Setting: University musculoskeletal laboratory. Patients or Other Participants: Sixteen healthy collegiate baseball players (age = 21.0 ± 1.6 years, height = 175.8 ± 10.2 cm, mass = 82.8 ± 4.3 kg). Intervention(s): Subjects threw a baseball from a single knee with maximum velocity (every 5 seconds) and rated their level of upper extremity exertion after every 20 throws. Subjects stopped after reporting above level 14 on the Borg scale and began posttests immediately. Main Outcome Measure(s): We measured active multijoint reproduction of 2 positions: arm cock and ball release. Dependent variables were absolute and variable error for 10 joint motions: scapulothoracic internal-external rotation, upward rotation, and posterior tilt; glenohumeral internal-external rotation, horizontal abduction-adduction, and flexion-extension; elbow pronation-supination and flexion-extension; and wrist ulnar-radial deviation and flexion-extension. We calculated acuity for each joint and the entire upper extremity using 3-dimensional variable error. Results: Fatigue occurred after an average of 62 ± 28 throws and increased 3-dimensional variable error scores (ie, decreased acuity) of the entire upper extremity and all joints in both positions (P < .05) except for the wrist in arm cock. Fatigue increased errors (ranging from 0.6° to 2.3°) at arm cock for scapulothoracic internal-external rotation, upward rotation, and posterior tilt; glenohumeral internal-external rotation and flexion-extension; elbow flexion

  19. Cutoff low systems and their relevance to large-scale extreme precipitation in the European Alps

    NASA Astrophysics Data System (ADS)

    Awan, N. K.; Formayer, H.

    2017-07-01

    In this paper, we attempt to highlight the relevance of cutoff low systems (CoLs) to large-scale heavy precipitation events within the Alpine region which often lead to catastrophic flooding. The main results of this study are (1) a detailed climatology (1971-1999) of CoLs for the European region, (2) contribution of CoLs to extreme precipitation events in the European Alpine region, (3) identification of regions within the European Alps most affected by extreme precipitation caused by CoLs, and (4) identification of regions where presence of CoLs is related to extreme precipitation in the Alpine region. The findings of this paper suggest that CoLs have a significant correlation with extreme precipitation events and strongly influence the climate of the Alpine region. The total contribution of CoLs to large-scale heavy precipitation events ranges between 20 and 95 % and is most pronounced in the northern and eastern parts of the Alps. More than 80 % of the events occur in the summer season. The area around the Alps and West of Spain (over the Atlantic Ocean) is the most affected region. The location of the center of CoLs that affect the Alpine region most occur on the northern and southern sides of the Alpine ridge.

  20. Genetic algorithm optimization of grating coupled near-field interference lithography systems at extreme numerical apertures

    NASA Astrophysics Data System (ADS)

    Bourke, Levi; Blaikie, Richard J.

    2017-09-01

    Grating coupled near-field interference lithography has the ability to produce deep-subwavelength interference patterns. Simulations of these systems is very computationally intensive. An inverse design procedure employing a genetic algorithm is utilized here to massively reduce the computational load and allow for the design of systems capable of interfering extremely high numerical apertures. This method is used to optimize systems with an interference patterns with a half pitch of λ /40 corresponding to a numerical aperture of 20. It is also used to demonstrate interference of higher | m| diffraction orders.

  1. Design implementation and migration of security systems as an extreme project.

    SciTech Connect

    Scharmer, Carol

    2010-10-01

    Decision Trees, algorithms, software code, risk management, reports, plans, drawings, change control, presentations, and analysis - all useful tools and efforts but time consuming, resource intensive, and potentially costly for projects that have absolute schedule and budget constraints. What are necessary and prudent efforts when a customer calls with a major security problem that needs to be fixed with a proven, off-the-approval-list, multi-layered integrated system with high visibility and limited funding and expires at the end of the Fiscal Year? Whether driven by budget cycles, safety, or by management decree, many such projects begin with generic scopes and funding allocated based on a rapid management 'guestimate.' Then a Project Manager (PM) is assigned a project with a predefined and potentially limited scope, compressed schedule, and potentially insufficient funding. The PM is tasked to rapidly and cost effectively coordinate a requirements-based design, implementation, test, and turnover of a fully operational system to the customer, all while the customer is operating and maintaining an existing security system. Many project management manuals call this an impossible project that should not be attempted. However, security is serious business and the reality is that rapid deployment of proven systems via an 'Extreme Project' is sometimes necessary. Extreme Projects can be wildly successful but require a dedicated team of security professionals lead by an experienced project manager using a highly-tailored and agile project management process with management support at all levels, all combined with significant interface with the customer. This paper does not advocate such projects or condone eliminating the valuable analysis and project management techniques. Indeed, having worked on a well-planned project provides the basis for experienced team members to complete Extreme Projects. This paper does, however, provide insight into what it takes for projects

  2. Design, implementation and migration of security systems as an extreme project.

    SciTech Connect

    Scharmer, Carol; Trujillo, David

    2010-08-01

    Decision Trees, algorithms, software code, risk management, reports, plans, drawings, change control, presentations, and analysis - all useful tools and efforts but time consuming, resource intensive, and potentially costly for projects that have absolute schedule and budget constraints. What are necessary and prudent efforts when a customer calls with a major security problem that needs to be fixed with a proven, off-the-approval-list, multi-layered integrated system with high visibility and limited funding and expires at the end of the Fiscal Year? Whether driven by budget cycles, safety, or by management decree, many such projects begin with generic scopes and funding allocated based on a rapid management 'guestimate.' Then a Project Manager (PM) is assigned a project with a predefined and potentially limited scope, compressed schedule, and potentially insufficient funding. The PM is tasked to rapidly and cost effectively coordinate a requirements-based design, implementation, test, and turnover of a fully operational system to the customer, all while the customer is operating and maintaining an existing security system. Many project management manuals call this an impossible project that should not be attempted. However, security is serious business and the reality is that rapid deployment of proven systems via an 'Extreme Project' is sometimes necessary. Extreme Projects can be wildly successful but require a dedicated team of security professionals lead by an experienced project manager using a highly-tailored and agile project management process with management support at all levels, all combined with significant interface with the customer. This paper does not advocate such projects or condone eliminating the valuable analysis and project management techniques. Indeed, having worked on a well-planned project provides the basis for experienced team members to complete Extreme Projects. This paper does, however, provide insight into what it takes for projects

  3. Photoelectric system for extreme solar limb darkening observation in different wavelengths with high resolution time.

    PubMed

    De Biase, G A

    1970-12-01

    The apparatus used by the Rome Astronomical Observatory expedition for the measurement of the extreme solar limb darkening at the total solar eclipse, on 7 March 1970, in Mexico, is described here. For the measurements, the method of Julius is followed. The apparatus consists of a photoelectric photometer with a mechanical chopper, which alternatively inserts the different color filters. The recording and command system is also described.

  4. Applying systems biology methods to the study of human physiology in extreme environments

    PubMed Central

    2013-01-01

    Systems biology is defined in this review as ‘an iterative process of computational model building and experimental model revision with the aim of understanding or simulating complex biological systems’. We propose that, in practice, systems biology rests on three pillars: computation, the omics disciplines and repeated experimental perturbation of the system of interest. The number of ethical and physiologically relevant perturbations that can be used in experiments on healthy humans is extremely limited and principally comprises exercise, nutrition, infusions (e.g. Intralipid), some drugs and altered environment. Thus, we argue that systems biology and environmental physiology are natural symbionts for those interested in a system-level understanding of human biology. However, despite excellent progress in high-altitude genetics and several proteomics studies, systems biology research into human adaptation to extreme environments is in its infancy. A brief description and overview of systems biology in its current guise is given, followed by a mini review of computational methods used for modelling biological systems. Special attention is given to high-altitude research, metabolic network reconstruction and constraint-based modelling. PMID:23849719

  5. Characteristics of mesoscale-convective-system-produced extreme rainfall over southeastern South Korea: 7 July 2009

    NASA Astrophysics Data System (ADS)

    Jeong, Jong-Hoon; Lee, Dong-In; Wang, Chung-Chieh; Han, In-Seong

    2016-04-01

    An extreme-rainfall-producing mesoscale convective system (MCS) associated with the Changma front in southeastern South Korea was investigated using observational data. This event recorded historic rainfall and led to devastating flash floods and landslides in the Busan metropolitan area on 7 July 2009. The aim of the present study is to analyse the influences for the synoptic and mesoscale environment, and the reasons that the quasi-stationary MCS causes extreme rainfall. Synoptic and mesoscale analyses indicate that the MCS and heavy rainfall occurred in association with a stationary front which resembled a warm front in structure. A strong southwesterly low-level jet (LLJ) transported warm and humid air and supplied the moisture toward the front, and the air rose upwards above the frontal surface. As the moist air was conditionally unstable, repeated upstream initiation of deep convection by back-building occurred at the coastline, while old cells moved downstream parallel to the convective line with training effect. Because the motion of convective cells nearly opposed the backward propagation, the system as a whole moved slowly. The back-building behaviour was linked to the convectively generated cold pool and its outflow boundary, which played a role in the propagation and maintenance of the rainfall system. As a result, the quasi-stationary MCS caused a prolonged duration of heavy rainfall, leading to extreme rainfall over the Busan metropolitan area.

  6. Development and recent results from the Subaru coronagraphic extreme adaptive optics system

    NASA Astrophysics Data System (ADS)

    Jovanovic, N.; Guyon, O.; Martinache, F.; Clergeon, C.; Singh, G.; Kudo, T.; Newman, K.; Kuhn, J.; Serabyn, E.; Norris, B.; Tuthill, P.; Stewart, P.; Huby, E.; Perrin, G.; Lacour, S.; Vievard, S.; Murakami, N.; Fumika, O.; Minowa, Y.; Hayano, Y.; White, J.; Lai, O.; Marchis, F.; Duchene, G.; Kotani, T.; Woillez, J.

    2014-07-01

    The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument is one of a handful of extreme adaptive optics systems set to come online in 2014. The extreme adaptive optics correction is realized by a combination of precise wavefront sensing via a non-modulated pyramid wavefront sensor and a 2000 element deformable mirror. This system has recently begun on-sky commissioning and was operated in closed loop for several minutes at a time with a loop speed of 800 Hz, on ~150 modes. Further suppression of quasi-static speckles is possible via a process called "speckle nulling" which can create a dark hole in a portion of the frame allowing for an enhancement in contrast, and has been successfully tested on-sky. In addition to the wavefront correction there are a suite of coronagraphs on board to null out the host star which include the phase induced amplitude apodization (PIAA), the vector vortex, 8 octant phase mask, 4 quadrant phase mask and shaped pupil versions which operate in the NIR (y-K bands). The PIAA and vector vortex will allow for high contrast imaging down to an angular separation of 1 λ/D to be reached; a factor of 3 closer in than other extreme AO systems. Making use of the left over visible light not used by the wavefront sensor is VAMPIRES and FIRST. These modules are based on aperture masking interferometry and allow for sub-diffraction limited imaging with moderate contrasts of ~100-1000:1. Both modules have undergone initial testing on-sky and are set to be fully commissioned by the end of 2014.

  7. Lichens as a Model-System for Symbiotic Organisms under Simulated Extreme Space Conditions

    NASA Astrophysics Data System (ADS)

    de Vera, J.; Horneck, G.; Rettberg, P.; Ott, S.

    As a consequence of the symbiotic state of lichens both the bionts are able to colonize habitats where the separate bionts would not be able to survive. The symbiosis of lichens reflects a high degree of complexity and plasticity. The combination of the different bionts enables these organisms to colonize most extreme habitats worldwide from the Arctic and Alpine zones to the Antarctic. Besides the already well investigated microorganisms lichens are good model -systems to examine adaptation strategies to most extreme environments. Because of the symbiotic nature of the lichens a 3-component -system can be used for investigations: the mycobiont (fungi), the photobiont (algae) and the lichen itself. Our investigations are based on such a system related to simulated extreme conditions. The influence of different doses of UV A, B, C (>200nm) on the vitality of fungal (mycobiont) fruiting bodys and their spores and the germination process has been investigated. The spores are cultivated on a variety of different substrates, especially on a Martian Regolith Simulant JSC - 1-A g a r- Extract for testing the influence of the UV radiation related to the dependency of different soil-substrate-extracts. The influence of vacuum conditions has been investigated. The aim of this research is to test the reaction of a symbiotic organism complex and its respective bionts to highly extreme space conditions looking forward to a possibly survival strategy of lichenized associations in space; probably supporting the theory of Panspermia. For the interpretation of results especially refering to the vitality potential of the photobionts in damaged and healthy lichens the method of modern confocal lasermicroscopy (CLSM) - a novel method in lichenology is presented.

  8. Integration, tests and laboratory performance of SAXO, the VLT-SPHERE extreme AO system

    NASA Astrophysics Data System (ADS)

    Petit, C.; Fusco, T.; Sauvage, J.-F.; Sevin, A.; Suarez, M.; Charton, J.; Baudoz, P.; Beuzit, J.-L.; Buey, T.; Dohlen, K.; Feautrier, P.; Fedrigo, E.; Fleuzry, B.; Gach, J.-L.; Hubin, N.; Kasper, M.; Mouillet, D.; Perret, D.; Puget, P.; Sinquin, J.-C.; Soenke, C.; Wildi, F.

    2011-09-01

    Direct detection and spectral characterization of extra-solar planets is one of the most exciting but also one of the most challenging areas in modern astronomy due to the very large contrast between the host star and the planet at very small angular separations. SPHERE (Spectro-Polarimetric High-contrast Exoplanet Research in Europe) is a second-generation instrument for the ESO VLT dedicated to this scientific objective. It combines an extreme adaptive optics system, various coronagraphic devices and a suite of focal instruments providing imaging, integral field spectroscopy and polarimetry capabilities in the visible and near-infrared spectral ranges. The extreme AO system, SAXO, is the heart of the SPHERE system, providing to the scientific instruments a flat wavefront corrected from all the atmospheric turbulence and internal defects. We will present a status of SAXO assembly integration and performance. The main requirements and system characteristics will be recalled, then each sub system will be individually presented and fully characterized and finally the full AO loop performance will be quantified. It will be demonstrated that SAXO will meet its challenging requirements (more than 90% of SR in H band with a residual jitter lower than 3 milli-arcseconds for average observation conditions on the VLT). Thanks to a coronagraphic analysis of the AO residuals, a detailed comparison between actual and simulated residual intensity profiles will be provided and will help to adjust the expected performance of the SPHERE system on sky, knowing that its first light is foreseen for mid 2012.

  9. [Effects of extremely low frequency electromagnetic radiation on cardiovascular system of workers].

    PubMed

    Zhao, Long-yu; Song, Chun-xiao; Yu, Duo; Liu, Xiao-liang; Guo, Jian-qiu; Wang, Chuan; Ding, Yuan-wei; Zhou, Hong-xia; Ma, Shu-mei; Liu, Xiao-dong; Liu, Xin

    2012-03-01

    To observe the exposure levels of extremely low frequency electromagnetic fields in workplaces and to analyze the effects of extremely low frequency electromagnetic radiation on cardiovascular system of occupationally exposed people. Intensity of electromagnetic fields in two workplaces (control and exposure groups) was detected with EFA-300 frequency electromagnetic field strength tester, and intensity of the noise was detected with AWA5610D integral sound level. The information of health physical indicators of 188 controls and 642 occupationally exposed workers was collected. Data were analyzed by SPSS17.0 statistic software. The intensity of electric fields and the magnetic fields in exposure groups was significantly higher than that in control group (P < 0.05), but there was no significant difference of noise between two workplaces (P > 0.05). The results of physical examination showed that the abnormal rates of HCY, ALT, AST, GGT, ECG in the exposure group were significantly higher than those in control group (P < 0.05). There were no differences of sex, age, height, weight between two groups (P > 0.05). Exposure to extremely low frequency electromagnetic radiation may have some effects on the cardiovascular system of workers.

  10. Extreme adaptive optics system optimization with the high order test bench

    NASA Astrophysics Data System (ADS)

    Vernet, Elise; Kasper, Markus; Vérinaud, Christophe; Fedrigo, Enrico; Tordo, Sébastien; Hubin, Norbert; Esposito, Simone; Pinna, Enrico; Puglisi, Alfio; Tozzi, Andrea; Basden, Alastair G.; Goodsell, Stephen J.; Love, Gordon D.; Myers, Richard M.

    2006-06-01

    Extreme adaptive optics systems dedicated to the search for extrasolar planets are currently being developed for most 8-10 meter telescopes. Extensive computer simulations have shown the ability of both Shack-Hartmann and pyramid wave front sensors to deliver high Strehl ratio correction expected from extreme adaptive optics but few experiments have been realized so far. The high order test bench implements extreme adaptive optics on the MACAO test bench with realistic telescope conditions reproduced by star and turbulence generators. A 32×32 actuator micro deformable mirror, one pyramid wave front sensor, one Shack-Hartmann wave front sensor, the ESO SPARTA real time computer and an essentially read-noise free electron multiplying CCD60 (E2V CCD60) provide an ideal cocoon to study the different behavior of the two types of wave front sensors in terms of linearity, sensitivity to calibration errors, noise propagation, specific issues to pyramid or Shack-Hartmann wave front sensors, etc. We will describe the overall design of this test bench and will focus on the characterization of two essential sub-systems: the micro deformable mirror and the phase screens.

  11. Compact multi-bounce projection system for extreme ultraviolet projection lithography

    DOEpatents

    Hudyma, Russell M.

    2002-01-01

    An optical system compatible with short wavelength (extreme ultraviolet) radiation comprising four optical elements providing five reflective surfaces for projecting a mask image onto a substrate. The five optical surfaces are characterized in order from object to image as concave, convex, concave, convex and concave mirrors. The second and fourth reflective surfaces are part of the same optical element. The optical system is particularly suited for ring field step and scan lithography methods. The invention uses aspheric mirrors to minimize static distortion and balance the static distortion across the ring field width, which effectively minimizes dynamic distortion.

  12. Minimizing System Noise Effects For Extreme-Scale Scientific Simulation Through Function Delegation

    SciTech Connect

    Dongarra, Jack J.; Bosilca, George

    2013-06-11

    The primary goal of the Minimizing System Noise Effects For Extreme-Scale Scientific Simulation through Function Delegation project is to eliminate or at best strongly minimize the impact of the noise introduced by the operating system, during large scale parallel applications runs. Collective communication operations are a basic building block for parallel programing models and scientific applications. These operations often dominate execution time of applications and tend to limit their scalability. In order to address this challenge, we evaluated different strategies to adapt the collective communications underlying topologies to the hardware architecture in order to provide increased levels of performance to the parallel applications.

  13. Mesosiderite clasts with the most extreme positive europium anomalies among solar system rocks

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, David W.; Rubin, Alan E.; Davis, Andrew M.

    1992-01-01

    Pigeonite-plagioclase gabbros that occur as clasts in mesosiderites (brecciated stony-iron meteorites) show extreme fractionations of the rare-earth elements (REEs) with larger positive europium anomalies than any previously known for igneous rocks from the earth, moon, or meteorite parent bodies and greater depletions of light REEs relative to heavy REEs than known for comparable cumulate gabbros. The REE pattern for merrillite in one of these clasts is depleted in light REEs and has a large positive europium anomaly as a result of metamorphic equilibration with the silicates. The extreme REE ratios exhibited by the mesosiderite clasts demonstrate that multistage igneous processes must have occurred on some asteroids in the early solar system. Melting of the crust by large-scale impacts or electrical induction from an early T-Tauri-phase sun may be responsible for these processes.

  14. Modelling Tradeoffs Evolution in Multipurpose Water Systems Operation in Response to Extreme Events

    NASA Astrophysics Data System (ADS)

    Mason, E.; Gazzotti, P.; Amigoni, F.; Giuliani, M.; Castelletti, A.

    2015-12-01

    Multipurpose water resource systems are usually operated on a tradeoff of the operating objectives, which - under steady state climatic and socio-economic boundary conditions - is supposed to ensure a fair and/or efficient balance among the conflicting interests. Extreme variability in the system's drivers might affect operators' risk aversion and force a change in the tradeoff. Properly accounting for these shifts is key to any rigorous retrospective assessment of operators' behavior and the associated system's performance. In this study, we explore how the selection of different optimal tradeoffs among the operating objectives is linked to the variations of the boundary conditions, such as, for example, drifting rainfall season or remarkable changes in crop and energy prices. We argue that tradeoff selection is driven by recent, extreme variations in system performance: underperforming on one of the operating objective target value should push the tradeoff toward the disadvantaged objective. To test this assumption, we developed a rational procedure to simulate the operators' tradeoff selection process. We map the selection onto a multi lateral negotiation process, where different multiple, virtual agents optimize different operating objectives. The agents periodically negotiate a compromise on the operating policy. The agent's rigidity in each negotiation round is determined by the recent system performances according to the specific objective it represents. The negotiation follows a set-based egocentric monotonic concession protocol: at each negotiation step an agent incrementally adds some options to the set of its acceptable compromises and (possibly) accepts lower and lower satisfying policies until an agreement is achieved. We apply this reiterated negotiation framework on the regulated Lake Como, Italy, simulating the lake dam operation and its recurrent updates over the last 50 years. The operation aims to balance shoreline flood prevention and irrigation

  15. Poststroke upper extremity rehabilitation: a review of robotic systems and clinical results.

    PubMed

    Brewer, Bambi R; McDowell, Sharon K; Worthen-Chaudhari, Lise C

    2007-01-01

    Although the use of robotic devices to address neuromuscular rehabilitative goals represents a promising technological advance in medical care, the large number of systems being developed and varying levels of clinical study of the devices make it difficult to follow and interpret the results in this new field. This article is a review of the current state-of-the-art in robotic applications in poststroke therapy for the upper extremity, written specifically to help clinicians determine the differences between various systems. We concentrate primarily on systems that have been tested clinically. Robotic systems are grouped by rehabilitation application (e.g., gross motor movement, bilateral training, etc.), and, where possible, the neurorehabilitation strategies employed by each system are described. We close with a discussion of the benefits and concerns of using robotics in rehabilitation and an indication of challenges that must be addressed for therapeutic robots to be applied practically in the clinic.

  16. Analysis and recent advances in gamma heating measurements in MINERVE facility by using TLD and OSLD techniques

    SciTech Connect

    Amharrak, H.; Di Salvo, J.; Lyoussi, A.; Roche, A.; Masson-Fauchier, M.; Bosq, J. C.

    2011-07-01

    The objective of this study is to develop nuclear heating measurement methods in Zero Power experimental reactors. This paper presents the analysis of Thermo-Luminescent Detector (TLD) and Optically Stimulated Luminescent Detectors (OSLD) experiments in the UO{sub 2} core of the MINERVE research reactor at the CEA Cadarache. The experimental sources of uncertainties on the gamma dose have been reduced by improving the conditions, as well as the repeatability, of the calibration step for each individual TLD. The interpretation of these measurements needs to take into account calculation of cavity correction factors, related to calibration and irradiation configurations, as well as neutron corrections calculations. These calculations are based on Monte Carlo simulations of neutron-gamma and gamma-electron transport coupled particles. TLD and OSLD are positioned inside aluminum pillboxes. The comparison between calculated and measured integral gamma-ray absorbed doses using TLD, shows that calculation slightly overestimates the measurement with a C/E value equal to 1.05 {+-} 5.3 % (k = 2). By using OSLD, the calculation slightly underestimates the measurement with a C/E value equal to 0.96 {+-} 7.0% (k = 2. (authors)

  17. Facilitating mathematics learning for students with upper extremity disabilities using touch-input system.

    PubMed

    Choi, Kup-Sze; Chan, Tak-Yin

    2015-03-01

    To investigate the feasibility of using tablet device as user interface for students with upper extremity disabilities to input mathematics efficiently into computer. A touch-input system using tablet device as user interface was proposed to assist these students to write mathematics. User-switchable and context-specific keyboard layouts were designed to streamline the input process. The system could be integrated with conventional computer systems only with minor software setup. A two-week pre-post test study involving five participants was conducted to evaluate the performance of the system and collect user feedback. The mathematics input efficiency of the participants was found to improve during the experiment sessions. In particular, their performance in entering trigonometric expressions by using the touch-input system was significantly better than that by using conventional mathematics editing software with keyboard and mouse. The participants rated the touch-input system positively and were confident that they could operate at ease with more practice. The proposed touch-input system provides a convenient way for the students with hand impairment to write mathematics and has the potential to facilitate their mathematics learning. Implications for Rehabilitation Students with upper extremity disabilities often face barriers to learning mathematics which is largely based on handwriting. Conventional computer user interfaces are inefficient for them to input mathematics into computer. A touch-input system with context-specific and user-switchable keyboard layouts was designed to improve the efficiency of mathematics input. Experimental results and user feedback suggested that the system has the potential to facilitate mathematics learning for the students.

  18. Opportunities for nonvolatile memory systems in extreme-scale high-performance computing

    DOE PAGES

    Vetter, Jeffrey S.; Mittal, Sparsh

    2015-01-12

    For extreme-scale high-performance computing systems, system-wide power consumption has been identified as one of the key constraints moving forward, where DRAM main memory systems account for about 30 to 50 percent of a node's overall power consumption. As the benefits of device scaling for DRAM memory slow, it will become increasingly difficult to keep memory capacities balanced with increasing computational rates offered by next-generation processors. However, several emerging memory technologies related to nonvolatile memory (NVM) devices are being investigated as an alternative for DRAM. Moving forward, NVM devices could offer solutions for HPC architectures. Researchers are investigating how to integratemore » these emerging technologies into future extreme-scale HPC systems and how to expose these capabilities in the software stack and applications. In addition, current results show several of these strategies could offer high-bandwidth I/O, larger main memory capacities, persistent data structures, and new approaches for application resilience and output postprocessing, such as transaction-based incremental checkpointing and in situ visualization, respectively.« less

  19. Opportunities for nonvolatile memory systems in extreme-scale high-performance computing

    SciTech Connect

    Vetter, Jeffrey S.; Mittal, Sparsh

    2015-01-12

    For extreme-scale high-performance computing systems, system-wide power consumption has been identified as one of the key constraints moving forward, where DRAM main memory systems account for about 30 to 50 percent of a node's overall power consumption. As the benefits of device scaling for DRAM memory slow, it will become increasingly difficult to keep memory capacities balanced with increasing computational rates offered by next-generation processors. However, several emerging memory technologies related to nonvolatile memory (NVM) devices are being investigated as an alternative for DRAM. Moving forward, NVM devices could offer solutions for HPC architectures. Researchers are investigating how to integrate these emerging technologies into future extreme-scale HPC systems and how to expose these capabilities in the software stack and applications. In addition, current results show several of these strategies could offer high-bandwidth I/O, larger main memory capacities, persistent data structures, and new approaches for application resilience and output postprocessing, such as transaction-based incremental checkpointing and in situ visualization, respectively.

  20. Complex network based techniques to identify extreme events and (sudden) transitions in spatio-temporal systems.

    PubMed

    Marwan, Norbert; Kurths, Jürgen

    2015-09-01

    We present here two promising techniques for the application of the complex network approach to continuous spatio-temporal systems that have been developed in the last decade and show large potential for future application and development of complex systems analysis. First, we discuss the transforming of a time series from such systems to a complex network. The natural approach is to calculate the recurrence matrix and interpret such as the adjacency matrix of an associated complex network, called recurrence network. Using complex network measures, such as transitivity coefficient, we demonstrate that this approach is very efficient for identifying qualitative transitions in observational data, e.g., when analyzing paleoclimate regime transitions. Second, we demonstrate the use of directed spatial networks constructed from spatio-temporal measurements of such systems that can be derived from the synchronized-in-time occurrence of extreme events in different spatial regions. Although there are many possibilities to investigate such spatial networks, we present here the new measure of network divergence and how it can be used to develop a prediction scheme of extreme rainfall events.

  1. Studies of the energy-momentum tensor in extreme-instability systems

    NASA Astrophysics Data System (ADS)

    Bergabo, Filip; Cantara, Michael; Mai, Manuel; Schweitzer, Peter

    2017-01-01

    The D-term is, like mass and spin, a fundamental property related to the energy-momentum tensor. Yet it is not known experimentally for any particle. In all theoretical studies so far the D-terms of various particles were found to be negative. Early works gave rise to the assumption that the negative sign could be related to stability. The emerging question is whether it is possible to find a field-theoretical system with a positive D-term. To shed some light on this question we investigate Q-clouds, an extreme parametric limit in the Q-ball system. Q-clouds are classically unstable solutions which delocalize, spread out over all space forming an infinitely dilute gas of free quanta, and are even energetically unstable against tunneling to plane waves. These extremely unstable field configurations provide an ideal candidate system for our purposes. By studying the energy-momentum tensor we show that at any stage of the Q-cloud limit one deals with perfectly well-defined and, when viewed in appropriately scaled coordinates, non-dissipating non-topological solitonic solutions. In particular, we show that Q-cloud solutions have negative D-terms, indicating that it is unlikely to realize a positive D-term in a consistent physical system. National Science Foundation, Contract No. 1406298.

  2. Feasibility of an Exoskeleton-Based Interactive Video Game System for Upper Extremity Burn Contractures.

    PubMed

    Schneider, Jeffrey C; Ozsecen, Muzaffer Y; Muraoka, Nicholas K; Mancinelli, Chiara; Della Croce, Ugo; Ryan, Colleen M; Bonato, Paolo

    2016-05-01

    Burn contractures are common and difficult to treat. Measuring continuous joint motion would inform the assessment of contracture interventions; however, it is not standard clinical practice. This study examines use of an interactive gaming system to measure continuous joint motion data. To assess the usability of an exoskeleton-based interactive gaming system in the rehabilitation of upper extremity burn contractures. Feasibility study. Eight subjects with a history of burn injury and upper extremity contractures were recruited from the outpatient clinic of a regional inpatient rehabilitation facility. Subjects used an exoskeleton-based interactive gaming system to play 4 different video games. Continuous joint motion data were collected at the shoulder and elbow during game play. Visual analog scale for engagement, difficulty and comfort. Angular range of motion by subject, joint, and game. The study population had an age of 43 ± 16 (mean ± standard deviation) years and total body surface area burned range of 10%-90%. Subjects reported satisfactory levels of enjoyment, comfort, and difficulty. Continuous joint motion data demonstrated variable characteristics by subject, plane of motion, and game. This study demonstrates the feasibility of use of an exoskeleton-based interactive gaming system in the burn population. Future studies are needed that examine the efficacy of tailoring interactive video games to the specific joint impairments of burn survivors. Copyright © 2016 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  3. Summertime Extremes in the Arctic Climate System: Understanding the 2012 Extreme Greenland Melt in the Context of the 1889 Episode

    NASA Astrophysics Data System (ADS)

    Neff, W. D.; Compo, G. P.; Webb, R. S.

    2013-12-01

    The last melting of the high Greenland ice sheet prior to 2012 occurred in 1889 and prior to that a number of times during the Medieval Warm Anomaly. In the case of the 2012 episode, key factors in the summer melt episode were a combination of 1) Central North American drought andheat wave, 2) Amplification of a polar trough-ridge pattern, 3) A positive excursion of the Atlantic Multi-Decadal Oscillation (AMO), and 4) Advection of warm moist air northward along the west coast of Greenland and thence over the ice sheet as an elevated thin liquid cloud layer. In both episodes, transport over the western Atlantic to Greenland in the form of 'Atmospheric Rivers,' thin filaments of high water vapor air, are observed in both the 20CR (which uses only historic global surface pressure measurements and sea-surface temperatures back to 1871) and satellite imagery. In the 2012 case, air mass changes associated with these transport events over Greenland were marked by rapid changes in observed isotope time series (Personal communications, Masson-Delmotte and Steen-Hansen). In this presentation, we use the 2012 episode to 'calibrate' the 20CR as a tool to examine past extreme events involving mid-latitude and northern ice sheet interaction. Of particular importance is determining the limits on 20CR-derived back-trajectory analyses: While the 2012 back-trajectories from modern reanalyses are fairly convincing in documenting the various transport paths, in 1889 the interpretation is complicated by the interplay of the propagation of ridge-trough patterns versus material transport coupled with the relatively coarse resolution of the 20CR. What we found in 1889 were two potential melt-inducing episodes in July. These episodes have many of the key factors seen in 2012: a positive AMO, moisture transport along the U.S. east coast, and warm-air transport from the west with some trajectories originating in the drought-stricken Dakota Territory.

  4. Self-Adaptive System based on Field Programmable Gate Array for Extreme Temperature Electronics

    NASA Technical Reports Server (NTRS)

    Keymeulen, Didier; Zebulum, Ricardo; Rajeshuni, Ramesham; Stoica, Adrian; Katkoori, Srinivas; Graves, Sharon; Novak, Frank; Antill, Charles

    2006-01-01

    In this work, we report the implementation of a self-adaptive system using a field programmable gate array (FPGA) and data converters. The self-adaptive system can autonomously recover the lost functionality of a reconfigurable analog array (RAA) integrated circuit (IC) [3]. Both the RAA IC and the self-adaptive system are operating in extreme temperatures (from 120 C down to -180 C). The RAA IC consists of reconfigurable analog blocks interconnected by several switches and programmable by bias voltages. It implements filters/amplifiers with bandwidth up to 20 MHz. The self-adaptive system controls the RAA IC and is realized on Commercial-Off-The-Shelf (COTS) parts. It implements a basic compensation algorithm that corrects a RAA IC in less than a few milliseconds. Experimental results for the cold temperature environment (down to -180 C) demonstrate the feasibility of this approach.

  5. [The Freehand System: an implantable neuroprosthesis for functional electrostimulation of the upper extremity].

    PubMed

    Fromm, B; Rupp, R; Gerner, H J

    2001-05-01

    We report on the first experience with the Freehand system in German-speaking countries, an implantable neuroprosthesis developed for the functional electrical stimulation of the upper extremity. Indications for its use are neurological deficits of the cervical spinal cord with active mobility of the shoulder and elbow flexion in tetraplegics, ideally in C5/6 tetraplegics. A further precondition for the implantation of this system is an intact reflex arc of the muscles that are to be stimulated, i.e. of the forearm and hand. Central defects such as hemiparesis, cerebral palsies or athetoid disorders or peripheral nerve palsies (e.g. brachial plexus lesions) are no good indications for the implantation of the Freehand system. We report on patient selection criteria, preoperative percutaneous electrical stimulation, the surgical procedure itself with optional active tendon transpositions, the intensive postoperative rehabilitation program until the patient is able to use the system independently and the life-long after-care.

  6. Perfusion Assessment with the SPY System after Arterial Venous Reversal for Upper Extremity Ischemia.

    PubMed

    Brooks, Darrell

    2014-07-01

    The timing and pattern of reperfusion following arterial- venous reversal (AVR) in patients with terminal ischemia of an upper extremity is not well understood. The current case series describes the timing and pattern of reperfusion observed in patients with terminal upper extremity ischemia who underwent AVR and repeated postoperative indocyanine green (ICG) angiography between 2004 and 2009. For all included patients, the SPY Near-Infrared Perfusion Assessment System permitted visualization of ICG-labeled blood flow for 60-second sampling periods at scheduled postoperative time points; outflow and rate and amplitude of inflow were objectively quantified with SPY-Q Analysis Toolkit image analysis software. The series comprised 6 male patients (mean age, 46 years) who presented with upper extremity ischemia related to hypothenar hammer syndrome (n = 2), embolism with patent foramen ovale (n = 2), atherosclerosis (n = 1), and avulsion amputation of the thumb (n = 1); the patient with the avulsion amputation was diagnosed with thromboangiitis obliterans at the time of replantation. AVR was successful in all 6 patients. In 5 of 6 patients, ICG angiography and SPY-based visualization/quantification showed that venous outflow and arterial inflow gradually normalized (versus unaffected digits) between postoperative days (PODs) 0 and 3 and was maintained at long-term follow-up (≥3 months); for the patient who underwent thumb replantation, perfusion normalized between POD 3 and month 5 follow-up. AVR effectively reestablished blood flow in patients with terminal upper extremity ischemia. ICG angiography with SPY technology revealed that, in most cases, kinetic curves, timing, and patterns of perfusion gradually normalized over several PODs.

  7. Perfusion Assessment with the SPY System after Arterial Venous Reversal for Upper Extremity Ischemia

    PubMed Central

    2014-01-01

    Background: The timing and pattern of reperfusion following arterial- venous reversal (AVR) in patients with terminal ischemia of an upper extremity is not well understood. Methods: The current case series describes the timing and pattern of reperfusion observed in patients with terminal upper extremity ischemia who underwent AVR and repeated postoperative indocyanine green (ICG) angiography between 2004 and 2009. For all included patients, the SPY Near-Infrared Perfusion Assessment System permitted visualization of ICG-labeled blood flow for 60-second sampling periods at scheduled postoperative time points; outflow and rate and amplitude of inflow were objectively quantified with SPY-Q Analysis Toolkit image analysis software. Results: The series comprised 6 male patients (mean age, 46 years) who presented with upper extremity ischemia related to hypothenar hammer syndrome (n = 2), embolism with patent foramen ovale (n = 2), atherosclerosis (n = 1), and avulsion amputation of the thumb (n = 1); the patient with the avulsion amputation was diagnosed with thromboangiitis obliterans at the time of replantation. AVR was successful in all 6 patients. In 5 of 6 patients, ICG angiography and SPY-based visualization/quantification showed that venous outflow and arterial inflow gradually normalized (versus unaffected digits) between postoperative days (PODs) 0 and 3 and was maintained at long-term follow-up (≥3 months); for the patient who underwent thumb replantation, perfusion normalized between POD 3 and month 5 follow-up. Conclusions: AVR effectively reestablished blood flow in patients with terminal upper extremity ischemia. ICG angiography with SPY technology revealed that, in most cases, kinetic curves, timing, and patterns of perfusion gradually normalized over several PODs. PMID:25426368

  8. Overview and Update of the North America Drought Monitor and North America Climate Extremes Monitoring System

    NASA Astrophysics Data System (ADS)

    Heim, R. R.

    2006-12-01

    The North America Drought Monitor (NADM) is a joint operational drought monitoring activity between scientists and other specialists in the United States, Mexico, and Canada. Like all weather phenomena, drought occurs irrespective of political and international boundaries. The monthly map and narrative product created by this first-of-its-kind effort provides an integrated continental-scale drought assessment tool for decision-makers in all three countries involved in drought monitoring, drought mitigation, and related climate services. The product is prepared by a rotating primary author who utilizes drought indicators which are computed using standard methodologies for stations across the continent, plus national drought monitoring products and feedback from local experts in each of the three countries. The participants include, within the United States: the NOAA National Climatic Data Center, NOAA Climate Prediction Center, USDA Joint Agricultural Weather Facility, and National Drought Mitigation Center; within Mexico: Servicio Meteorologico Nacional/Comision Nacional del Agua; and within Canada: Agriculture and Agrifood Canada and the Meteorological Service of Canada. The NADM is part of a North America Climate Extremes Monitoring (NACEM) system which will monitor and assess climate extremes across the continent. Several climate indicators are currently computed from station daily data to measure (in addition to drought) heavy precipitation, heat waves, and cold waves. Future efforts will add indicators to monitor storm severity and severe weather, including the creation of a North America Climate Extremes Index (NACEI) patterned after the U.S. Climate Extremes Index (USCEI). This presentation will review the history of the NADM/NACEM effort, the data utilized, the indicators computed, and the product preparation and peer review process.

  9. Characterization of TLD-100 micro-cubes for use in small field dosimetry

    NASA Astrophysics Data System (ADS)

    Peña-Jiménez, Salvador; Lárraga-Gutiérrez, José Manuel; García-Garduño, Olivia Amanda; Gamboa-deBuen, Isabel

    2014-11-01

    At present there are no international regulations for the management of millimeter scale fields and there are no suggestions for a reference detector to perform the characterization and dose determination for unconventional radiation beams (small fields) so that the dosimetry of small fields remains an open research field worldwide because these fields are used in radiotherapy treatments. Sensitivity factors and reproducibility of TLD-100 micro-cubes (1×1×1 mm3) were determinate irradiating the dosimeters with a 6 MV beam in a linear accelerator dedicated to radiosurgery at the Instituto Nacional de Neurología y Neurocirugía (INNN). Thermoluminescent response as a function of dose was determined for doses in water between 0.5 and 3 Gy and two field sizes (2×2 cm2 and 10×10 cm2). It was found that the response is linear over the dose range studied and it does not depend on field size.

  10. TLD environmental monitoring at the Institute of Nuclear Engineering in Brazil.

    PubMed

    Taam, I H; da Rosa, L A R; Crispim, V R

    2008-09-01

    Since 2003 the Institute of Nuclear Engineering in Rio de Janeiro city, Brazil, operates a new cyclotron, RDS-111, to produce (18)F-Fluorodeoxyglucose to be used in nuclear medicine. Additionally, the IEN radioactive waste repository has been enlarged during the past last years, receiving a considerable amount of radioactive materials. Therefore, it became necessary to evaluate a possible increase of the environmental gamma exposure rates at the institute site due to the operation of the new accelerator and the enlargement of the institute waste repository as well. LiF:Mg,Cu,P, TLD-100H, and TL detectors were employed for environmental kerma rate evaluation and the results were compared with previous results obtained before the RDS-111 operation initialisation and the enlargement of IEN waste repository. No significant contribution for the enhancement of environmental gamma kerma rates was detected.

  11. Characterization of TLD-100 micro-cubes for use in small field dosimetry

    SciTech Connect

    Peña-Jiménez, Salvador Gamboa-deBuen, Isabel; Lárraga-Gutiérrez, José Manuel E-mail: amanda.garcia.g@gmail.com; García-Garduño, Olivia Amanda E-mail: amanda.garcia.g@gmail.com

    2014-11-07

    At present there are no international regulations for the management of millimeter scale fields and there are no suggestions for a reference detector to perform the characterization and dose determination for unconventional radiation beams (small fields) so that the dosimetry of small fields remains an open research field worldwide because these fields are used in radiotherapy treatments. Sensitivity factors and reproducibility of TLD-100 micro-cubes (1×1×1 mm3) were determinate irradiating the dosimeters with a 6 MV beam in a linear accelerator dedicated to radiosurgery at the Instituto Nacional de Neurología y Neurocirugía (INNN). Thermoluminescent response as a function of dose was determined for doses in water between 0.5 and 3 Gy and two field sizes (2×2 cm2 and 10×10 cm2). It was found that the response is linear over the dose range studied and it does not depend on field size.

  12. Modeling of the Human - Operator in a Complex System Functioning Under Extreme Conditions

    NASA Astrophysics Data System (ADS)

    Getzov, Peter; Hubenova, Zoia; Yordanov, Dimitar; Popov, Wiliam

    2013-12-01

    Problems, related to the explication of sophisticated control systems of objects, operating under extreme conditions, have been examined and the impact of the effectiveness of the operator's activity on the systems as a whole. The necessity of creation of complex simulation models, reflecting operator's activity, is discussed. Organizational and technical system of an unmanned aviation complex is described as a sophisticated ergatic system. Computer realization of main subsystems of algorithmic system of the man as a controlling system is implemented and specialized software for data processing and analysis is developed. An original computer model of a Man as a tracking system has been implemented. Model of unmanned complex for operators training and formation of a mental model in emergency situation, implemented in "matlab-simulink" environment, has been synthesized. As a unit of the control loop, the pilot (operator) is simplified viewed as an autocontrol system consisting of three main interconnected subsystems: sensitive organs (perception sensors); central nervous system; executive organs (muscles of the arms, legs, back). Theoretical-data model of prediction the level of operator's information load in ergatic systems is proposed. It allows the assessment and prediction of the effectiveness of a real working operator. Simulation model of operator's activity in takeoff based on the Petri nets has been synthesized.

  13. Resonance Raman Spectroscopy of Extreme Nanowires and Other 1D Systems

    PubMed Central

    Smith, David C.; Spencer, Joseph H.; Sloan, Jeremy; McDonnell, Liam P.; Trewhitt, Harrison; Kashtiban, Reza J.; Faulques, Eric

    2016-01-01

    This paper briefly describes how nanowires with diameters corresponding to 1 to 5 atoms can be produced by melting a range of inorganic solids in the presence of carbon nanotubes. These nanowires are extreme in the sense that they are the limit of miniaturization of nanowires and their behavior is not always a simple extrapolation of the behavior of larger nanowires as their diameter decreases. The paper then describes the methods required to obtain Raman spectra from extreme nanowires and the fact that due to the van Hove singularities that 1D systems exhibit in their optical density of states, that determining the correct choice of photon excitation energy is critical. It describes the techniques required to determine the photon energy dependence of the resonances observed in Raman spectroscopy of 1D systems and in particular how to obtain measurements of Raman cross-sections with better than 8% noise and measure the variation in the resonance as a function of sample temperature. The paper describes the importance of ensuring that the Raman scattering is linearly proportional to the intensity of the laser excitation intensity. It also describes how to use the polarization dependence of the Raman scattering to separate Raman scattering of the encapsulated 1D systems from those of other extraneous components in any sample. PMID:27168195

  14. [Design of optical system for solar extreme-ultraviolet imaging spectrometer].

    PubMed

    Liu, Zhuang; Gong, Yan

    2012-03-01

    Hyper-spectral imaging observation of the sun in the EUV region is an important method of research for solar's upper transition region, corona and plasma's physical property. Based on the application objective of solar extreme ultraviolet imaging spectrometer (SEUIS), combined with the current states of domestic and foreign extreme ultraviolet imaging spectrometer, a few of parameters for SEUIS design were drew up in the present paper. The advantages and disadvantages of all kinds of optical configurations were discussed,and the configuration of combination of telescope and spectrometer was chosen. The available main components were also described, off-axis parabolic mirror was chosen for telescope, and a high density uniform-line-space toroidal grating for dispersion device. The optical system which satisfies the performance parameters was designed. The design process, detailed parameters and results were presented in the end. The working wavelength of the optics system is 17.0-21.0 nm, the field of view is 1 228" x 1 024", the spatial resolution is 0.8 arc sec x pixel(-1), the spectral resolution is about 0.00198 nm x pixel(-1), and the total length of system is about 2.8 m.

  15. Dosimetry for Small Fields in Stereotactic Radiosurgery Using Gafchromic MD-V2-55 Film, TLD-100 and Alanine Dosimeters

    PubMed Central

    Massillon-JL, Guerda; Cueva-Prócel, Diego; Díaz-Aguirre, Porfirio; Rodríguez-Ponce, Miguel; Herrera-Martínez, Flor

    2013-01-01

    This work investigated the suitability of passive dosimeters for reference dosimetry in small fields with acceptable accuracy. Absorbed dose to water rate was determined in nine small radiation fields with diameters between 4 and 35 mm in a Leksell Gamma Knife (LGK) and a modified linear accelerator (linac) for stereotactic radiosurgery treatments. Measurements were made using Gafchromic film (MD-V2-55), alanine and thermoluminescent (TLD-100) dosimeters and compared with conventional dosimetry systems. Detectors were calibrated in terms of absorbed dose to water in 60Co gamma-ray and 6 MV x-ray reference (10×10 cm2) fields using an ionization chamber calibrated at a standards laboratory. Absorbed dose to water rate computed with MD-V2-55 was higher than that obtained with the others dosimeters, possibly due to a smaller volume averaging effect. Ratio between the dose-rates determined with each dosimeter and those obtained with the film was evaluated for both treatment modalities. For the LGK, the ratio decreased as the dosimeter size increased and remained constant for collimator diameters larger than 8 mm. The same behaviour was observed for the linac and the ratio increased with field size, independent of the dosimeter used. These behaviours could be explained as an averaging volume effect due to dose gradient and lack of electronic equilibrium. Evaluation of the output factors for the LGK collimators indicated that, even when agreement was observed between Monte Carlo simulation and measurements with different dosimeters, this does not warrant that the absorbed dose to water rate in the field was properly known and thus, investigation of the reference dosimetry should be an important issue. These results indicated that alanine dosimeter provides a high degree of accuracy but cannot be used in fields smaller than 20 mm diameter. Gafchromic film can be considered as a suitable methodology for reference dosimetry. TLD dosimeters are not appropriate in fields

  16. Treatment of Diabetic Foot Ulcers through Systemic Effects of Extremely Low Frequency Electromagnetic Fields

    NASA Astrophysics Data System (ADS)

    Trejo-Núñez, A. D.; Pérez-Chávez, F.; García-Sánchez, C.; Serrano-Luna, G.; Cañendo-Dorantes, L.

    2008-08-01

    This study was designed to, investigate the healing effects of extremely low frequency electromagnetic fields (ELF-EMF) on diabetic foot ulcers and test two different exposure systems aimed at reducing the ELF-EMF exposure time of patients. In the first system the ELF-EMF were applied to the arm where only 3% of the total blood volume/min circulates at any given time. In the second system the ELF-EMF were applied to the thorax where more than 100% of the total blood volume/minute circulates at any given time. Twenty-six diabetic patients, with superficial neuropathic ulcers unresponsive to medical treatment were included in this preliminary report. In the first group (17 patients), the arm was exposed two hours twice a week to a extremely low frequency electromagnetic field of 0.45-0.9 mTrms, 120 Hz generated inside a solenoid coil of 10.1 cm by 20.5 cm long. In the second group the thorax of 7 patients was exposed 25 minutes twice a week to an electromagnetic field of 0.4-0.85 mTrms, 120 Hz generated in the center of a squared quasi-Helmholtz coil 52 cm by side. One patient was assigned to a placebo configuration of each exposure system with identical appearance as the active equipment but without magnetic field. Patients with deep ulcers, infected ulcers, cancer, or auto-immune disease were excluded. These preliminary results showed that the two exposure systems accelerate the healing process of neuropathic ulcers. Complete healing of the ulcer had a median duration of 90 days in both exposure systems. Therefore thorax exposure where more blood is exposed to ELF-EMF per unit of time was able to reduce 4.8 times the patient treatment time. In those patients assigned to the placebo equipment no healing effects were observed. This study will continue with a parallel, double blind placebo controlled protocol.

  17. Compilation of 1986 annual reports of the Navy ELF (Extremely Low Frequency) communications system ecological monitoring program, volume 3

    NASA Astrophysics Data System (ADS)

    1987-07-01

    This is the fifth compilation of annual reports for the Navy's Extremely Low Frequency (ELF) Communications System Ecological Monitoring Program. This report documents the progress of the following studies: aquatic ecosystems, wetland studies, and bird species and communities.

  18. Experimental evaluation and performance optimization of a flash lamp pumped Er: Glass laser system over temperature extremes

    NASA Astrophysics Data System (ADS)

    Shrivastava, Sachendra K.; Soni, Lokesh; Chaudhari, Ravindra Y.

    2013-05-01

    Experimental evaluation of a flash lamp pumped Er: glass laser over temperature extremes is presented. In this study, first behavior of flash lamp pumped Er: glass laser system has been experimentally investigated over temperature extremes. Next, the generated data during experimentation has been analyzed and system parameters are optimized such that fairly constant laser output is maintained over temperature extremes. This work also enables the development of a compact, simple, low cost, light weight, low repetition rate and high peak power laser source working in eye safe region for defense application.

  19. Can we colonize the solar system? Human biology and survival in the extreme space environment.

    PubMed

    Launius, Roger D

    2010-09-01

    Throughout the history of the space age the dominant vision for the future has been great spaceships plying the solar system, and perhaps beyond, moving living beings from one planet to another. Spacesuited astronauts would carry out exploration, colonization, and settlement as part of a relentlessly forward looking movement of humanity beyond Earth. As time has progressed this image has not changed appreciably even as the full magnitude of the challenges it represents have become more and more apparent. This essay explores the issues associated with the human movement beyond Earth and raises questions about whether humanity will ever be able to survive in the extreme environment of space and the other bodies of the solar system. This paper deals with important historical episodes as well as wider conceptual issues about life in space. Two models of expansion beyond Earth are discussed: (1) the movement of microbes and other types of life on Earth that can survive the space environment and (2) the modification of humans into cyborgs for greater capability to survive in the extreme environments encountered beyond this planet.

  20. DISCOVERY OF A BRIGHT, EXTREMELY LOW MASS WHITE DWARF IN A CLOSE DOUBLE DEGENERATE SYSTEM

    SciTech Connect

    Vennes, S.; Kawka, A.; Nemeth, P.; Thorstensen, J. R.; Skinner, J. N.; Pigulski, A.; Steslicki, M.; Kolaczkowski, Z.; Srodka, P.

    2011-08-10

    We report the discovery of a bright (V {approx} 13.7), extremely low mass white dwarf in a close double degenerate system. We originally selected GALEX J171708.5+675712 for spectroscopic follow-up among a group of white dwarf candidates in an ultraviolet-optical reduced proper-motion diagram. The new white dwarf has a mass of 0.18 M{sub sun} and is the primary component of a close double degenerate system (P = 0.246137 days, K{sub 1} = 288 km s{sup -1}) comprising a fainter white dwarf secondary with M{sub 2} {approx} 0.9 M{sub sun}. Light curves phased with the orbital ephemeris show evidence of relativistic beaming and weaker ellipsoidal variations. The light curves also reveal secondary eclipses (depth {approx}8 mmag) while the primary eclipses appear partially compensated by the secondary gravitational deflection and are below detection limits. Photospheric abundance measurements show a nearly solar composition of Si, Ca, and Fe (0.1-1 sun), while the normal kinematics suggest a relatively recent formation history. Close binary evolutionary scenarios suggest that extremely low mass white dwarfs form via a common-envelope phase and possible Roche lobe overflow.

  1. Case Studies of Extreme Space Weather Effects on the New York State (NYS) Electric Power System

    NASA Astrophysics Data System (ADS)

    Chantale Damas, M.; Mohamed, Ahmed; Ngwira, Chigomyezo

    2017-04-01

    New York State (NYS) is home to one of the largest urban cities in the world, New York City (NYC). Understanding and mitigating the effects of extreme space weather events are important to reduce the vulnerabilities of the NYS present bulk power system, which includes NYC. Extreme space weather events perturb Earth's magnetic field and generate geo-electric fields that result in the flow of Geomagnetically Induced Currents (GICs) through transmission lines, followed by transformers and ground. GICs find paths to ground through transformer grounding wires causing half-cycle saturation to their magnetic cores. This causes transformers to overheat, inject harmonics to the grid and draw more reactive power than normal. Overheating, if sustained for a long duration, may lead to transformer failure or lifetime reduction. Presented work uses results from simulations performed by the Global SWMF-generated ground geomagnetic field perturbations. Results from computed values of simulated induced geo-electric fields at specific ground-based active INTERMAGNET magnetometer sites, combined with NYS electricity transmission network real data are used to examine the vulnerabilities of the NYS power grid. As an urban city with a large population, NYC is especially vulnerable and the results from this research can be used to model power systems for other urban cities.

  2. Planetary Collisions Outside the Solar System: Time Domain Characterization of Extreme Debris Disks

    NASA Astrophysics Data System (ADS)

    Meng, Huan Y. A.; Su, Kate Y. L.; Rieke, George H.; Rujopakarn, Wiphu; Myers, Gordon; Cook, Michael; Erdelyi, Emery; Maloney, Chris; McMath, James; Persha, Gerald; Poshyachinda, Saran; Reichart, Daniel E.

    2015-05-01

    Luminous debris disks of warm dust in the terrestrial planet zones around solar-like stars were recently found to vary, which is indicative of ongoing large-scale collisions of rocky objects. We use Spitzer 3.6 and 4.5 μm time-series observations in 2012 and 2013 (extended to 2014 in one case) to monitor five more debris disks with unusually high fractional luminosities (“extreme debris disk”), including P1121 in the open cluster M47 (80 Myr), HD 15407A in the AB Dor moving group (80 Myr), HD 23514 in the Pleiades (120 Myr), HD 145263 in the Upper Sco Association (10 Myr), and the field star BD+20 307 (≳1 Gyr). Together with the published results for ID8 in NGC 2547 (35 Myr), this makes the first systematic time-domain investigation of planetary impacts outside the solar system. Significant variations with timescales shorter than a year are detected in five out of the six extreme debris disks we monitored. However, different systems show diverse sets of characteristics in the time domain, including long-term decay or growth, disk temperature variations, and possible periodicity.

  3. Planetary Collisions outside the Solar System: Time Domain Characterization of Extreme Debris Disks

    NASA Astrophysics Data System (ADS)

    Meng, Huan; Su, Kate Y. L.; Rieke, George

    2015-01-01

    Luminous debris disks of warm dust in the terrestrial planet zones around solar-like stars are recently found to vary, indicative of ongoing collisions of rocky objects. We use Spitzer 3.6 and 4.5 micron time-series observations in 2012 and 2013 to monitor 5 more extreme debris disks, including P1121 in the open cluster M47 (80 Myr), HD 15407A in the AB Dor moving group (80 Myr), HD 23514 in the Pleiades (120 Myr), HD 145263 in the Upper Sco Association (10 Myr), and the field star BD+20 207 (>1 Gyr). Together with the published results for ID8 in NGC 2547 (35 Myr), this makes the first systematic time-domain investigation of planetary impacts outside the solar system. Significant variations with timescales shorter than a year are detected in five out of the six extreme debris disks we have monitored. However, different systems show diverse sets of characteristics in the time domain, including long-term trends, disk temperature variations, and possible periodicity.

  4. A Non-detection Of Star-Planet Interaction In The Extreme Wasp-18 System

    NASA Astrophysics Data System (ADS)

    Miller, Brendan P.; Gallo, E.; Wright, J. T.; Dupree, A. K.

    2012-05-01

    We report recent observations of the extreme WASP-18 system, which features a massive close-in transiting planet (Mp = 10.1 Mjup, P = 0.94 d) orbiting a young F6 star. WASP-18 was targeted as an ideal testbed for investigating potential magnetic (or tidal) interactions between "hot Jupiters" and their host stars. The high-resolution echelle spectrograph MIKE was used on the 6.5m Magellan Clay telescope to obtain 13 spectra spanning planetary orbital phases of 0.7-0.4, while the X-ray Telescope on Swift provided contemporaneous monitoring with a stacked exposure of 50 ks. We find that the cores of the Ca II H and K lines do not show significant variability over 8 d, in contrast to the expectation of phase-dependent chromospheric activity enhancements for efficient star-planet interaction. The star is also X-ray faint, with log Lx < 27.5, indicating that coronal activity is likewise low. Consequently, any observable star-planet interaction in this extreme system must be at best highly transient. We additionally comment on general observational challenges to establishing robust detections of star-planet interaction. Our results suggest that the immediate utility of star-planet interaction to estimate exoplanet magnetic field strengths may be limited.

  5. Complex networks identify spatial patterns of extreme rainfall of the South American monsoon system

    NASA Astrophysics Data System (ADS)

    Boers, Niklas; Bokkhagen, Bodo; Marwan, Norbert; Kurths, Jürgen; Marengo, Jose

    2014-05-01

    In this study, we investigate the spatial characteristics of extreme rainfall synchronicity of the South American Monsoon System (SAMS) by means of Complex Networks. We first show how this approach leads to the identification of linkages between large-scale atmospheric conditions and natural hazards occurring at the earth's surface. Thereafter, we exemplify how our methodology can be used to compare different datasets and to test the performance of climate models. In recent years, complex networks have attracted great attention for analyzing the spatial characteristics of interrelations of various time series. Outstanding examples in this context are functional brain networks as well as so-called climate networks. In most approaches, the basic idea is to represent time series at different locations by network nodes, which will be connected by network links if the corresponding time series behave similar. Information on the spatial characteristics of these similarities can be inferred by network measures quantifying different aspects of the networks' topology. By combining several network measures and interpreting them in a climatic context, we investigate climatic linkages and classify the spatial characteristics of extreme rainfall synchronicity. Although our approach is based on only one variable (high spatiotemporal resolution rainfall), it reveals the most important features of the SAMS, such as the main moisture pathways, areas with frequent development of Mesoscale Convective Systems, and the major convergence zones. We will show that these features are only partially reproduced by reanalysis and (regional and global) climate model data.

  6. An early validation of the Society for Vascular Surgery lower extremity threatened limb classification system.

    PubMed

    Cull, David L; Manos, Ginger; Hartley, Michael C; Taylor, Spence M; Langan, Eugene M; Eidt, John F; Johnson, Brent L

    2014-12-01

    The Society for Vascular Surgery (SVS) recently established the Lower Extremity Threatened Limb Classification System, a staging system using Wound characteristic, Ischemia, and foot Infection (WIfI) to stratify the risk for limb amputation at 1 year. Although intuitive in nature, this new system has not been validated. The purpose of the following study was to determine whether the WIfI system is predictive of limb amputation and wound healing. Between 2007 and 2010, we prospectively obtained data related to wound characteristics, extent of infection, and degree of postrevascularization ischemia in 139 patients with foot wounds who presented for lower extremity revascularization (158 revascularization procedures). After adapting those data to the WIfI classifications, we analyzed the influence of wound characteristics, extent of infection, and degree of ischemia on time to wound healing; empirical Kaplan-Meier survival curves were compared with theoretical outcomes predicted by WIfI expert consensus opinion. Of the 158 foot wounds, 125 (79%) healed. The median time to wound healing was 2.7 months (range, 1-18 months). Factors associated with wound healing included presence of diabetes mellitus (P = .013), wound location (P = .049), wound size (P = .007), wound depth (P = .004), and degree of ischemia (P < .001). The WIfI clinical stage was predictive of 1-year limb amputation (stage 1, 3%; stage 2, 10%; stage 3, 23%; stage 4, 40%) and wound nonhealing (stage 1, 8%; stage 2, 10%; stage 3, 23%; stage 4, 40%) and correlated with the theoretical outcome estimated by the SVS expert panel. The theoretical framework for risk stratification among patients with critical limb ischemia provided by the SVS expert panel appears valid. Further validation of the WIfI classification system with multicenter data is justified. Copyright © 2014 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  7. Using Rollback Avoidance to Mitigate Failures in Next-Generation Extreme-Scale Systems

    SciTech Connect

    Levy, Scott N.

    2016-05-01

    High-performance computing (HPC) systems enable scientists to numerically model complex phenomena in many important physical systems. The next major milestone in the development of HPC systems is the construction of the rst supercomputer capable executing more than an exa op, 1018 oating point operations per second. On systems of this scale, failures will occur much more frequently than on current systems. As a result, resilience is a key obstacle to building next-generation extremescale systems. Coordinated checkpointing is currently the most widely-used mechanism for handling failures on HPC systems. Although coordinated checkpointing remains e ective on current systems, increasing the scale of today's systems to build next-generation systems will increase the cost of fault tolerance as more and more time is taken away from the application to protect against or recover from failure. Rollback avoidance techniques seek to mitigate the cost of checkpoint/restart by allowing an application to continue its execution rather than rolling back to an earlier checkpoint when failures occur. These techniqes include failure prediction and preventive migration, replicated computation, fault-tolerant algorithms, and softwarebased memory fault correction. In this thesis, we examine how rollback avoidance techniques can be used to address failures on extreme-scale systems. Using a combination of analytic modeling and simulation, we evaluate the potential impact of rollback avoidance on these systems. We then present a novel rollback avoidance technique that exploits similarities in application memory. Finally, we examine the feasibility of using this technique to protect against memory faults in kernel memory.

  8. Lazy Checkpointing : Exploiting Temporal Locality in Failures to Mitigate Checkpointing Overheads on Extreme-Scale Systems

    SciTech Connect

    Tiwari, Devesh; Gupta, Saurabh; Vazhkudai, Sudharshan S

    2014-01-01

    Continuing increase in the computational power of supercomputers has enabled large-scale scientific applications in the areas of astrophysics, fusion, climate and combustion to run larger and longer-running simulations, facilitating deeper scientific insights. However, these long-running simulations are often interrupted by multiple system failures. Therefore, these applications rely on ``checkpointing'' as a resilience mechanism to store application state to permanent storage and recover from failures. \\\\ \\indent Unfortunately, checkpointing incurs excessive I/O overhead on supercomputers due to large size of checkpoints, resulting in a sub-optimal performance and resource utilization. In this paper, we devise novel mechanisms to show how checkpointing overhead can be mitigated significantly by exploiting the temporal characteristics of system failures. We provide new insights and detailed quantitative understanding of the checkpointing overheads and trade-offs on large-scale machines. Our prototype implementation shows the viability of our approach on extreme-scale machines.

  9. Non-invasive hypoglycemia monitoring system using extreme learning machine for Type 1 diabetes.

    PubMed

    Ling, Sai Ho; San, Phyo Phyo; Nguyen, Hung T

    2016-09-01

    Hypoglycemia is a very common in type 1 diabetic persons and can occur at any age. It is always threatening to the well-being of patients with Type 1 diabetes mellitus (T1DM) since hypoglycemia leads to seizures or loss of consciousness and the possible development of permanent brain dysfunction under certain circumstances. Because of that, an accurate continuing hypoglycemia monitoring system is a very important medical device for diabetic patients. In this paper, we proposed a non-invasive hypoglycemia monitoring system using the physiological parameters of electrocardiography (ECG) signal. To enhance the detection accuracy, extreme learning machine (ELM) is developed to recognize the presence of hypoglycemia. A clinical study of 16 children with T1DM is given to illustrate the good performance of ELM.

  10. Strategies for spectroscopy on extremely large telescopes - III. Remapping switched fibre systems

    NASA Astrophysics Data System (ADS)

    Poppett, C. L.; Allington-Smith, J. R.; Murray, G. J.

    2009-10-01

    We explore the use of remapping techniques to improve the efficiency of highly multiplexed fibre systems for astronomical spectroscopy. This is particularly important for the implementation of diverse field spectroscopy (DFS) using highly multiplexed monolithic fibre systems (MFS). DFS allows arbitrary distributions of target regions to be addressed to optimize observing efficiency when observing complex, clumpy structures such as protoclusters which will be increasingly accessible to extremely large telescopes. We show how the adoption of various types of remapping between the input and output of an MFS can allow contiguous regions of spatial elements to be selected using only simple switch arrays. Finally, we show how this compares in efficiency with integral-field and multi-object spectroscopy by simulations using artificial and real catalogues of objects. With the adoption of these mapping strategies, DFS outperforms other techniques when addressing a range of realistic target distributions. These techniques are also applicable to biomedical science and were in fact inspired by it.

  11. Identification of nonlinear system using extreme learning machine based Hammerstein model

    NASA Astrophysics Data System (ADS)

    Tang, Yinggan; Li, Zhonghui; Guan, Xinping

    2014-09-01

    In this paper, a new method for nonlinear system identification via extreme learning machine neural network based Hammerstein model (ELM-Hammerstein) is proposed. The ELM-Hammerstein model consists of static ELM neural network followed by a linear dynamic subsystem. The identification of nonlinear system is achieved by determining the structure of ELM-Hammerstein model and estimating its parameters. Lipschitz quotient criterion is adopted to determine the structure of ELM-Hammerstein model from input-output data. A generalized ELM algorithm is proposed to estimate the parameters of ELM-Hammerstein model, where the parameters of linear dynamic part and the output weights of ELM neural network are estimated simultaneously. The proposed method can obtain more accurate identification results with less computation complexity. Three simulation examples demonstrate its effectiveness.

  12. SAXO, the SPHERE extreme AO system: on-sky final performance and future improvements

    NASA Astrophysics Data System (ADS)

    Fusco, T.; Sauvage, J.-F.; Mouillet, D.; Costille, A.; Petit, C.; Beuzit, J.-L.; Dohlen, K.; Milli, J.; Girard, J.; Kasper, M.; Vigan, A.; Suarez, M.; Soenke, C.; Downing, M.; N'Diaye, M.; Baudoz, P.; Sevin, A.; Baruffolo, A.; Schmid, H.-M.; Salasnich, B.; Hugot, E.; Hubin, N.

    2016-07-01

    The SPHERE (Spectro-Polarimetric High-contrast Exoplanet Research) instrument aims at detecting extremely faint sources (giant extrasolar planets) in the vicinity of bright stars1. Such a challenging goal requires the use of a very-high-order performance Adaptive Optics [AO] system feeding the scientific instruments with a quasi-perfect flat wave front corrected from all the atmospheric turbulence and internal defects. This AO system, called SAXO (Sphere Ao for eXoplanet Observation) is the heart of the instrument, a heart beating 1200 time per second and providing unprecedented image quality for a large ground based telescope at optical/near infrared wavelength. We will present the latest results obtained on-sky, demonstrating its exceptional performance (in terms of correction quality, stability and robustness) and tremendous potentiality for high contrast imaging and more specifically for exoplanet discovery.

  13. System characterization of RiceWrist-S: a forearm-wrist exoskeleton for upper extremity rehabilitation.

    PubMed

    Pehlivan, Ali Utku; Rose, Chad; O'Malley, Marcia K

    2013-06-01

    Rehabilitation of the distal joints of the upper extremities is crucial to restore the ability to perform activities of daily living to patients with neurological lesions resulting from stroke or spinal cord injury. Robotic rehabilitation has been identified as a promising new solution, however, much of the existing technology in this field is focused on the more proximal joints of the upper arm. A recently presented device, the RiceWrist-S, focuses on the rehabilitation of the forearm and wrist, and has undergone a few important design changes. This paper first addresses the design improvements achieved in the recent design iteration, and then presents the system characterization of the new device. We show that the RiceWrist-S has capabilities beyond other existing devices, and exhibits favorable system characteristics as a rehabilitation device, in particular torque output, range of motion, closed loop position performance, and high spatial resolution.

  14. Climate engineering of vegetated land for hot extremes mitigation: An Earth system model sensitivity study

    NASA Astrophysics Data System (ADS)

    Wilhelm, Micah; Davin, Edouard L.; Seneviratne, Sonia I.

    2015-04-01

    Various climate engineering schemes have been proposed as a way to curb anthropogenic climate change. Land climate engineering schemes aiming to reduce the amount of solar radiation absorbed at the surface by changes in land surface albedo have been considered in a limited number of investigations. However, global studies on this topic have generally focused on the impacts on mean climate rather than extremes. Here we present the results of a series of transient global climate engineering sensitivity experiments performed with the Community Earth System Model over the time period 1950-2100 under historical and Representative Concentration Pathway 8.5 scenarios. Four sets of experiments are performed in which the surface albedo over snow-free vegetated grid points is increased respectively by 0.05, 0.10, 0.15, and 0.20. The simulations show a preferential cooling of hot extremes relative to mean temperatures throughout the Northern midlatitudes during boreal summer under the late twentieth century conditions. Two main mechanisms drive this response: On the one hand, a stronger efficacy of the albedo-induced radiative forcing on days with high incoming shortwave radiation and, on the other hand, enhanced soil moisture-induced evaporative cooling during the warmest days relative to the control simulation due to accumulated soil moisture storage and reduced drying. The latter effect is dominant in summer in midlatitude regions and also implies a reduction of summer drought conditions. It thus constitutes another important benefit of surface albedo modifications in reducing climate change impacts. The simulated response for the end of the 21st century conditions is of the same sign as that for the end of the twentieth century conditions but indicates an increasing absolute impact of land surface albedo increases in reducing mean and extreme temperatures under enhanced greenhouse gas forcing.

  15. New Extreme Trans-Neptunian Objects: Towards A Super-Earth In Our Solar System Beyond A Few Hundred AU

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott S.; Trujillo, Chadwick A.; Tholen, David J.

    2016-10-01

    We are conducting the widest and deepest survey ever obtained for extreme distant solar system objects. Our goal is to increase understanding of the origin of extremely high perihelion objects like Sedna and 2012 VP113. We also want to determine if the extreme trans-Neptunian objects cluster in their orbital angles, which would be an indication of a yet unobserved massive shepherding planet in the distant solar system, as first shown in Trujillo and Sheppard (2014). Our survey, started in 2012, has covered about 2000 square degrees to over 24th magnitude using the wide-field imagers on the Subaru 8 meter and CTIO 4 meter telescopes. We have found several new extreme solar system objects and inner Oort cloud objects as well as discovered the first outer Oort cloud object with a perihelion beyond Neptune. We will discuss these objects along with several other interesting objects discovered in our ongoing survey.

  16. Understanding and Exploiting Spatial Properties of System Failures on Extreme-Scale HPC Systems

    SciTech Connect

    Rogers, James H; Maxwell, Don E

    2015-01-01

    As we approach exascale, the scientific simulations are expected to experience more interruptions due to increased system failures. Designing better HPC resilience techniques requires understanding the key characteristics of system failures on these systems. While temporal properties of system failures on HPC systems have been well-investigated, there is limited understanding about the spatial characteristics of system failures and its impact on the resilience mechanisms. Therefore, we examine the spatial characteristics and behavior of system failures. We investigate the interaction between spatial and temporal characteristics of failures and its implications for system operations and resilience mechanisms on large-scale HPC systems. We show that system failures have spatial locality at different granularity in the system; study impact of different failure-types; and investigate the correlation among different failure-types. Finally, we propose a novel scheme that exploits the spatial locality in failures to improve application and system performance. Our evaluation shows that the proposed scheme significantly improves the system performance in a dynamic and production-level HPC system.

  17. Handbook for the extremely low frequency (ELF) data acquisition and analysis system

    NASA Astrophysics Data System (ADS)

    Vrbancich, J.; Valentine-Flint, S.; Wong, R.

    1994-10-01

    This handbook describes the digital data acquisition system built to record data in the 1 Hz to 600 Hz bandwidth from the portable underwater extremely low frequency (ELF) electromagnetic sensor unit. The sensors supported by the acquisition system are three-axis alternating magnetic field detection coils, three-axis alternating electric field sensors (electrodes) and three-axis seismic sensors; plus ancillary sensors such as pressure-depth, inclination and compass heading. The data acquisition system consists of the wet-end electronics package incorporating the controller board, 16 bit analog to digital converter, low noise preamplifiers etc. and the dry-end electronics unit incorporating the power supply and computer. The data acquisition software for remote control of the total system and the analysis software which is linked to the data acquisition system is also presented. The analysis software which is purposely designed as an integral part of the acquisition system provides frequency domain spectral information (via the fast Fourier transform algorithm) from the raw time series data and may be used both for quick look analysis during the data acquisition phase and for full analysis of data in slow time.

  18. Ada (Trade Name) Compiler, Validation Summary Report: TLD Systems Ltd. TLD VAX/1750A Ada Compiler System. Version 1.0.0., MicroVAX II Host and TLD 1750A Instruction.

    DTIC Science & Technology

    1987-06-22

    Y" An illegal- external file name that either contains invalid characters, or is too long if no invalid characters exist. $FILE NAME WITH WILD CARD CHAR...34XYZ’" An external file name that either contains a wild card character, or is too lon& if no wild card character exists. $GREATER THAN DURATION

  19. How extreme are extremes?

    NASA Astrophysics Data System (ADS)

    Cucchi, Marco; Petitta, Marcello; Calmanti, Sandro

    2016-04-01

    High temperatures have an impact on the energy balance of any living organism and on the operational capabilities of critical infrastructures. Heat-wave indicators have been mainly developed with the aim of capturing the potential impacts on specific sectors (agriculture, health, wildfires, transport, power generation and distribution). However, the ability to capture the occurrence of extreme temperature events is an essential property of a multi-hazard extreme climate indicator. Aim of this study is to develop a standardized heat-wave indicator, that can be combined with other indices in order to describe multiple hazards in a single indicator. The proposed approach can be used in order to have a quantified indicator of the strenght of a certain extreme. As a matter of fact, extremes are usually distributed in exponential or exponential-exponential functions and it is difficult to quickly asses how strong was an extreme events considering only its magnitude. The proposed approach simplify the quantitative and qualitative communication of extreme magnitude

  20. Absolute intensity calibration of the Wendelstein 7-X high efficiency extreme ultraviolet overview spectrometer system

    NASA Astrophysics Data System (ADS)

    Greiche, Albert; Biel, Wolfgang; Marchuk, Oleksandr; Burhenn, Rainer

    2008-09-01

    The new high effiency extreme ultraviolet overview spectrometer (HEXOS) system for the stellarator Wendelstein 7-X is now mounted for testing and adjustment at the tokamak experiment for technology oriented research (TEXTOR). One part of the testing phase was the intensity calibration of the two double spectrometers which in total cover a spectral range from 2.5 to 160.0 nm with overlap. This work presents the current intensity calibration curves for HEXOS and describes the method of calibration. The calibration was implemented with calibrated lines of a hollow cathode light source and the branching ratio technique. The hollow cathode light source provides calibrated lines from 16 up to 147 nm. We could extend the calibrated region in the spectrometers down to 2.8 nm by using the branching line pairs emitted by an uncalibrated pinch extreme ultraviolet light source as well as emission lines from boron and carbon in TEXTOR plasmas. In total HEXOS is calibrated from 2.8 up to 147 nm, which covers most of the observable wavelength region. The approximate density of carbon in the range of the minor radius from 18 to 35 cm in a TEXTOR plasma determined by simulating calibrated vacuum ultraviolet emission lines with a transport code was 5.5×1017 m-3 which corresponds to a local carbon concentration of 2%.

  1. Adaption to extreme rainfall with open urban drainage system: an integrated hydrological cost-benefit analysis.

    PubMed

    Zhou, Qianqian; Panduro, Toke Emil; Thorsen, Bo Jellesmark; Arnbjerg-Nielsen, Karsten

    2013-03-01

    This paper presents a cross-disciplinary framework for assessment of climate change adaptation to increased precipitation extremes considering pluvial flood risk as well as additional environmental services provided by some of the adaptation options. The ability of adaptation alternatives to cope with extreme rainfalls is evaluated using a quantitative flood risk approach based on urban inundation modeling and socio-economic analysis of corresponding costs and benefits. A hedonic valuation model is applied to capture the local economic gains or losses from more water bodies in green areas. The framework was applied to the northern part of the city of Aarhus, Denmark. We investigated four adaptation strategies that encompassed laissez-faire, larger sewer pipes, local infiltration units, and open drainage system in the urban green structure. We found that when taking into account environmental amenity effects, an integration of open drainage basins in urban recreational areas is likely the best adaptation strategy, followed by pipe enlargement and local infiltration strategies. All three were improvements compared to the fourth strategy of no measures taken.

  2. Copahue Geothermal System: A Volcanic Environment with Rich Extreme Prokaryotic Biodiversity.

    PubMed

    Urbieta, María Sofía; Porati, Graciana Willis; Segretín, Ana Belén; González-Toril, Elena; Giaveno, María Alejandra; Donati, Edgardo Rubén

    2015-07-08

    The Copahue geothermal system is a natural extreme environment located at the northern end of the Cordillera de los Andes in Neuquén province in Argentina. The geochemistry and consequently the biodiversity of the area are dominated by the activity of the Copahue volcano. The main characteristic of Copahue is the extreme acidity of its aquatic environments; ponds and hot springs of moderate and high temperature as well as Río Agrio. In spite of being an apparently hostile location, the prokaryotic biodiversity detected by molecular ecology techniques as well as cultivation shows a rich and diverse environment dominated by acidophilic, sulphur oxidising bacteria or archaea, depending on the conditions of the particular niche studied. In microbial biofilms, found in the borders of the ponds where thermal activity is less intense, the species found are completely different, with a high presence of cyanobacteria and other photosynthetic species. Our results, collected during more than 10 years of work in Copahue, have enabled us to outline geomicrobiological models for the different environments found in the ponds and Río Agrio. Besides, Copahue seems to be the habitat of novel, not yet characterised autochthonous species, especially in the domain Archaea.

  3. Copahue Geothermal System: A Volcanic Environment with Rich Extreme Prokaryotic Biodiversity

    PubMed Central

    Urbieta, María Sofía; Willis Porati, Graciana; Segretín, Ana Belén; González-Toril, Elena; Giaveno, María Alejandra; Donati, Edgardo Rubén

    2015-01-01

    The Copahue geothermal system is a natural extreme environment located at the northern end of the Cordillera de los Andes in Neuquén province in Argentina. The geochemistry and consequently the biodiversity of the area are dominated by the activity of the Copahue volcano. The main characteristic of Copahue is the extreme acidity of its aquatic environments; ponds and hot springs of moderate and high temperature as well as Río Agrio. In spite of being an apparently hostile location, the prokaryotic biodiversity detected by molecular ecology techniques as well as cultivation shows a rich and diverse environment dominated by acidophilic, sulphur oxidising bacteria or archaea, depending on the conditions of the particular niche studied. In microbial biofilms, found in the borders of the ponds where thermal activity is less intense, the species found are completely different, with a high presence of cyanobacteria and other photosynthetic species. Our results, collected during more than 10 years of work in Copahue, have enabled us to outline geomicrobiological models for the different environments found in the ponds and Río Agrio. Besides, Copahue seems to be the habitat of novel, not yet characterised autochthonous species, especially in the domain Archaea. PMID:27682093

  4. Optimization of an on-board imaging system for extremely rapid radiation therapy

    SciTech Connect

    Cherry Kemmerling, Erica M.; Wu, Meng Yang, He; Fahrig, Rebecca; Maxim, Peter G.; Loo, Billy W.

    2015-11-15

    Purpose: Next-generation extremely rapid radiation therapy systems could mitigate the need for motion management, improve patient comfort during the treatment, and increase patient throughput for cost effectiveness. Such systems require an on-board imaging system that is competitively priced, fast, and of sufficiently high quality to allow good registration between the image taken on the day of treatment and the image taken the day of treatment planning. In this study, three different detectors for a custom on-board CT system were investigated to select the best design for integration with an extremely rapid radiation therapy system. Methods: Three different CT detectors are proposed: low-resolution (all 4 × 4 mm pixels), medium-resolution (a combination of 4 × 4 mm pixels and 2 × 2 mm pixels), and high-resolution (all 1 × 1 mm pixels). An in-house program was used to generate projection images of a numerical anthropomorphic phantom and to reconstruct the projections into CT datasets, henceforth called “realistic” images. Scatter was calculated using a separate Monte Carlo simulation, and the model included an antiscatter grid and bowtie filter. Diagnostic-quality images of the phantom were generated to represent the patient scan at the time of treatment planning. Commercial deformable registration software was used to register the diagnostic-quality scan to images produced by the various on-board detector configurations. The deformation fields were compared against a “gold standard” deformation field generated by registering initial and deformed images of the numerical phantoms that were used to make the diagnostic and treatment-day images. Registrations of on-board imaging system data were judged by the amount their deformation fields differed from the corresponding gold standard deformation fields—the smaller the difference, the better the system. To evaluate the registrations, the pointwise distance between gold standard and realistic registration

  5. Measurements of gamma dose and thermal neutron fluence in phantoms exposed to a BNCT epithermal beam with TLD-700.

    PubMed

    Gambarini, G; Magni, D; Regazzoni, V; Borroni, M; Carrara, M; Pignoli, E; Burian, J; Marek, M; Klupak, V; Viererbl, L

    2014-10-01

    Gamma dose and thermal neutron fluence in a phantom exposed to an epithermal neutron beam for boron neutron capture therapy (BNCT) can be measured by means of a single thermoluminescence dosemeter (TLD-700). The method exploits the shape of the glow curve (GC) and requires the gamma-calibration GC (to obtain gamma dose) and the thermal-neutron-calibration GC (to obtain neutron fluence). The method is applicable for BNCT dosimetry in case of epithermal neutron beams from a reactor because, in most irradiation configurations, thermal neutrons give a not negligible contribution to the TLD-700 GC. The thermal neutron calibration is not simple, because of the impossibility of having thermal neutron fields without gamma contamination, but a calibration method is here proposed, strictly bound to the method itself of dose separation. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. The evolution of energy-transducing systems. Studies with an extremely halophilic archaebacterium

    NASA Technical Reports Server (NTRS)

    Stan-Lotter, Helga

    1991-01-01

    The halobacterial ATPase was labeled with C-14-dicyclohexylcarbodiimide and subunit 2 of the enzyme was prepared by electroelution. Subunit 2 was cleaved by several chemical and enzymatic procedures for further preparation of peptides. Immunoreactions (Western blotting) of halobacterial membranes were performed with an antiserum against subunit A of the vacuolar ATPase from Neurospora crassa. A 85 K band (subunit 1) from the membranes of H saccharovorum and from two halobacterial isolates, which were isolated from Permian salt sediments, reacted strongly with the antiserum. The ATPase from the latter isolates resembled the ATPase from H saccharovorum, but had a higher content of acidic amino acids. If it can be verified that the age of the bacterial isolates is in the same range as when deposition of salt occurred, an extremely interesting system for the study of evolutionary questions would be available, since the salt-embedded bacteria presumably did not undergo mutational and selectional events.

  7. Cellular and molecular pathways of extremely-low-frequency electromagnetic field interactions with living systems

    SciTech Connect

    Tenforde, T.S.

    1992-06-01

    There is growing evidence that environmental electric and magnetic fields in the extremely-low-frequency (ELF) band below 300 Hz can influence biological functions by mechanisms that are only poorly understood at the present time. The primary objectives of this paper are to review the physical properties of ELF fields, their interactions with living systems at the tissue, cellular, and subcellular levels, and the key role of cell membranes ;in the transduction of signals from imposed ELF fields. Topics of discussion include signal-to-noise ratios for single cells and cell aggregates, resonance phenomena involving a combination of static and ELF magnetic fields, and the possible influence of ELF fields on molecular signaling pathways that involve membrane receptors and cytoplasmic second messengers.

  8. Cellular and molecular pathways of extremely-low-frequency electromagnetic field interactions with living systems

    SciTech Connect

    Tenforde, T.S.

    1992-06-01

    There is growing evidence that environmental electric and magnetic fields in the extremely-low-frequency (ELF) band below 300 Hz can influence biological functions by mechanisms that are only poorly understood at the present time. The primary objectives of this paper are to review the physical properties of ELF fields, their interactions with living systems at the tissue, cellular, and subcellular levels, and the key role of cell membranes ;in the transduction of signals from imposed ELF fields. Topics of discussion include signal-to-noise ratios for single cells and cell aggregates, resonance phenomena involving a combination of static and ELF magnetic fields, and the possible influence of ELF fields on molecular signaling pathways that involve membrane receptors and cytoplasmic second messengers.

  9. Impact of an absorbent silver-eluting dressing system on lower extremity revascularization wound complications.

    PubMed

    Childress, Beverly B; Berceli, Scott A; Nelson, Peter R; Lee, W Anthony; Ozaki, C Keith

    2007-09-01

    Surgical wounds for lower extremity revascularization are prone to infection and dehiscence. Acticoat Absorbent, an antimicrobial dressing, offers sustained release of ionic silver. We hypothesized that immediate application of Acticoat as a postoperative dressing would reduce wound complications in patients undergoing leg revascularization. All infrainguinal revascularization cases involving leg incisions at a single Veterans Administration Medical Center were identified from July 1, 2002, to September 30, 2005. The control group received conventional dressings, while the treatment group received an Acticoat dressing. Wound complication rates were captured via National Surgical Quality Improvement Program data. Patient characteristics and procedure distributions were similar between groups. The wound complication rate fell 64% with utilization of the Acticoat-based dressing (control 14% [17/118], treatment 5% [7/130]; P = 0.016). An Acticoat-based dressing system offers a potentially useful, cost-effective adjunct to reduce open surgical leg revascularization wound complications.

  10. Invisible marking system by extreme ultraviolet radiation: the new frontier for anti-counterfeiting tags

    NASA Astrophysics Data System (ADS)

    Di Lazzaro, P.; Bollanti, S.; Flora, F.; Mezi, L.; Murra, D.; Torre, A.; Bonfigli, F.; Montereali, R. M.; Vincenti, M. A.

    2016-07-01

    We present a marking technology which uses extreme ultraviolet radiation to write invisible patterns on tags based on alkali fluoride thin films. The shape of the pattern is pre-determined by a mask (in the case of contact lithography) or by a suitable mirror (projection lithography). Tags marked using this method offer a much better protection against fakes than currently available anti-counterfeiting techniques. The complexity and cost of this technology can be tailored to the value of the good to be protected, leaving, on the other hand, the specific reading technique straightforward. So far, we have exploited our invisible marking to tag artworks, identity cards, electrical components, and containers of radioactive wastes. Advantages and limits of this technology are discussed in comparison with the anti-counterfeiting systems available in the market.

  11. Creation of a neo-aortoiliac system from lower extremity deep and superficial veins.

    PubMed Central

    Clagett, G P; Bowers, B L; Lopez-Viego, M A; Rossi, M B; Valentine, R J; Myers, S I; Chervu, A

    1993-01-01

    OBJECTIVE: This study evaluated the morbidity, mortality, and intermediate term follow-up of patients undergoing replacement of their aortoiliac-femoral systems with lower extremity deep and superficial veins. SUMMARY BACKGROUND DATA: The most commonly used treatment for aortic prosthetic infection is ectopic bypass and removal of the prosthesis. The overall mortality rate with this approach is approximately 20%, with an amputation rate of 10% to 14%. Other limitations include thrombosis of the ectopic bypass leading to limb loss, reinfection of the ectopic bypass, and aortic stump blowout. Dissatisfaction with this approach has led the authors to develop the following. METHODS: A neo-aortoiliac system (NAIS) was fashioned from lower extremity deep veins (DV), greater saphenous veins (GSV), or both in patients with infected aortobifemoral prosthesis (n = 17) and other complex aortic problems (n = 3). Removal of infected prosthetic material, harvest of vein, and creation of NAIS was performed as a single-staged procedure. RESULTS: The in-hospital mortality and amputation rates were 10% each. The mean (+/- standard deviation [SD]) operative time was 6.5 +/- 1.8 hours and the blood transfusion requirement was 4 +/- 3 units. Four patients experienced postoperative gastrointestinal complications with peritonitis and sepsis; NAIS vein graft resisted infection and remained intact. The mean follow-up time was 22.5 +/- 16 months. NAISs constructed from GSVs were prone to the development of focal stenoses requiring intervention or diffuse neointimal hyperplasia leading to occlusion. In contrast, all NAISs from larger caliber DVs have remained widely patent. The failure rate of GSV NAISs was 64%, compared to 0% for DV NAISs (p = 0.006). Despite the high failure rate in patients with GSV NAISs, none has required amputation. In patients who had DVs harvested for NAIS reconstruction, limb edema and other signs of venous hypertension have been minimal. CONCLUSION: NAIS

  12. ASAS J083241+2332.4: A New Extreme Low Mass Ratio Overcontact Binary System

    NASA Astrophysics Data System (ADS)

    Sriram, K.; Malu, S.; Choi, C. S.; Vivekananda Rao, P.

    2016-03-01

    We present the R- and V-band CCD photometry and Hα line studies of an overcontact binary ASAS J083241+2332.4. The light curves exhibit totality along with a trace of the O’Connell effect. The photometric solution indicates that this system falls into the category of extreme low-mass ratio overcontact binaries with a mass ratio, q ˜ 0.06. Although a trace of the O’ Connell effect is observed, constancy of the Hα line along various phases suggest that a relatively higher magnetic activity is needed for it to show a prominent fill-in effect. The study of O-C variations reveals that the period of the binary shows a secular increase at the rate of dP/dt ˜ 0.0765 s years-1, which is superimposed by a low, but significant, sinusoidal modulation with a period of ˜8.25 years. Assuming that the sinusoidal variation is due to the presence of a third body, orbital elements have been derived. There exist three other similar systems, SX Crv, V857 Her, and E53, which have extremely low mass ratios and we conclude that ASAS J083241+2332.4 resembles SX Crv in many respects. Theoretical studies indicate that at a critical mass ratio range, qcritical = 0.07-0.09, overcontact binaries should merge and form a fast rotating star, but it has been suggested that qcritical can continue to fall up to 0.05 depending on the primary's mass and structure. Moreover, the obtained fill-out factors (50%-70%) indicate that mass loss is considerable and hydrodynamical simulations advocate that mass loss from L2 is mandatory for a successful merging process. Comprehensively, the results indicate that ASAS J083241+2332.4 is at a stage of merger. The pivotal role played by the subtle nature of the derived mass ratio in forming a rapidly rotating star has been discussed.

  13. Influence of Extreme Hydrologic Events on the Occurrence of Microbial Species in Regional Groundwater Systems

    NASA Astrophysics Data System (ADS)

    Rudolph, D.

    2009-05-01

    The mobility of microbial species originating from surface sources such as animal manure is influenced both by the intrinsic permeability of the subsurface sediment and by the nature of the hydrologic driving factors associated with climatic variability. Extreme hydrologic events such as exceptionally heavy periods of precipitation or snowmelt represent conditions that may produce rapid infiltration and potential redistribution of microbial loads through surface runoff. In this study, the occurrence of various bacterial indicator species (total coliforms (TC), aerobic endospores and E. coli) was tracked in a network of over 20 monitoring wells situated in a vulnerable wellhead protection area of a municipal well field located near Woodstock, Ontario during snow melt periods. Water quality, hydraulic head and groundwater temperature were also monitored during the course of the investigation. The wells were situated along a groundwater flow path at various depths below the water table and sampled frequently throughout an annual cycle. Samples were also obtained from surface water and tile drains during winter and spring melt and from the municipal wells. The data indicate that the elevated microbial concentrations in both the tile drains and shallow aquifer system correlate to ephemeral hydrologic events that develop during intense melt periods. Surface runoff mobilizes microbial species from significant distances away from the municipal wells to within the immediate vicinity of the wells, significantly increasing the potential for capture in the municipal supply subsequently increasing the risk water quality. Higher concentrations in the shallow aquifer systems were observed in response to ephemeral hydrologic events, yet occurrence in the municipal wells was very infrequent even under these conditions of high vulnerability. The occurrence patterns in the municipal wells, however, appear to correlate to the snowmelt periods, although after a significant time lag

  14. Woven Thermal Protection System Based Heat-shield for Extreme Entry Environments Technology (HEEET)

    NASA Technical Reports Server (NTRS)

    Chinnapongse, Ronald; Ellerbe, Donald; Stackpoole, Maragaret; Venkatapathy, Ethiraj; Beerman, Adam; Feldman, Jay; Peterson Keith; Prabhu, Dinesh; Dillman, Robert; Munk, Michelle

    2013-01-01

    NASA's future robotic missions utilizing an entry system into Venus and the outer planets, namely, Saturn, Uranus, Neptune, result in extremely severe entry conditions that exceed the capabilities of state of the art low to mid density ablators such as PICA or Avcoat. Therefore mission planners typically assume the use of a fully dense carbon phenolic heat shield similar to what was flown on Pioneer Venus and Galileo. Carbon phenolic (CP) is a robust TPS material however its high density and relatively high thermal conductivity constrain mission planners to steep entries, with high heat fluxes and pressures and short entry durations, in order for CP to be feasible from a mass perspective. The high entry conditions pose challenges for certification in existing ground based test facilities and the longer-­-term sustainability of CP will continue to pose challenges. In 2012 the Game Changing Development Program (GCDP) in NASA's Space Technology Mission Directorate funded NASA ARC to investigate the feasibility of a Woven Thermal Protection System (WTPS) to meet the needs of NASA's most challenging entry missions. This project was highly successful demonstrating that a Woven TPS solution compares favorably to CP in performance in simulated reentry environments and provides the opportunity to manufacture graded materials that should result in overall reduced mass solutions and enable a much broader set of missions than does CP. Building off the success of the WTPS project GCDP has funded a follow on project to further mature and scale up the WTPS concept for insertion into future NASA robotic missions. The matured WTPS will address the CP concerns associated with ground based test limitations and sustainability. This presentation will briefly discuss results from the WTPS Project and the plans for WTPS maturation into a heat-­-shield for extreme entry environment.

  15. Woven Thermal Protection System Based Heat-shield for Extreme Entry Environments Technology (HEEET)

    NASA Technical Reports Server (NTRS)

    Ellerby, Donald; Venkatapathy, Ethiraj; Stackpoole, Margaret; Chinnapongse, Ronald; Munk, Michelle; Dillman, Robert; Feldman, Jay; Prabhu, Dinesh; Beerman, Adam

    2013-01-01

    NASA's future robotic missions utilizing an entry system into Venus and the outer planets, namely, Saturn, Uranus, Neptune, result in extremely high entry conditions that exceed the capabilities of state of the art low to mid density ablators such as PICA or Avcoat. Therefore mission planners typically assume the use of a fully dense carbon phenolic heat shield similar to what was flown on Pioneer Venus and Galileo. Carbon phenolic is a robust TPS material however its high density and relatively high thermal conductivity constrain mission planners to steep entries, with high heat fluxes and pressures and short entry durations, in order for CP to be feasible from a mass perspective. The high entry conditions pose challenges for certification in existing ground based test facilities and the longer-term sustainability of CP will continue to pose challenges. In 2012 the Game Changing Development Program (GCDP) in NASA's Space Technology Mission Directorate funded NASA ARC to investigate the feasibility of a Woven Thermal Protection System (WTPS) to meet the needs of NASA's most challenging entry missions. This project was highly successful demonstrating that a Woven TPS solution compares favorably to CP in performance in simulated reentry environments and provides the opportunity to manufacture graded materials that should result in overall reduced mass solutions and enable a much broader set of missions than does CP. Building off the success of the WTPS project GCDP has funded a follow on project to further mature and scale up the WTPS concept for insertion into future NASA robotic missions. The matured WTPS will address the CP concerns associated with ground based test limitations and sustainability. This presentation will briefly discuss results from the WTPS Project and the plans for WTPS maturation into a heat-shield for extreme entry environment.

  16. Wafer and reticle positioning system for the Extreme Ultraviolet Lithography Engineering Test Stand

    SciTech Connect

    WRONOSKY,JOHN B.; SMITH,TONY G.; CRAIG,MARCUS J.; STURGIS,BEVERLY R.; DARNOLD,JOEL R.; WERLING,DAVID K.; KINCY,MARK A.; TICHENOR,DANIEL A.; WILLIAMS,MARK E.; BISCHOFF,PAUL

    2000-01-27

    This paper is an overview of the wafer and reticle positioning system of the Extreme Ultraviolet Lithography (EUVL) Engineering Test Stand (ETS). EUVL represents one of the most promising technologies for supporting the integrated circuit (IC) industry's lithography needs for critical features below 100nm. EUVL research and development includes development of capabilities for demonstrating key EUV technologies. The ETS is under development at the EUV Virtual National Laboratory, to demonstrate EUV full-field imaging and provide data that supports production-tool development. The stages and their associated metrology operated in a vacuum environment and must meet stringent outgassing specifications. A tight tolerance is placed on the stage tracking performance to minimize image distortion and provide high position repeatability. The wafer must track the reticle with less than {+-}3nm of position error and jitter must not exceed 10nm rms. To meet these performance requirements, magnetically levitated positioning stages utilizing a system of sophisticated control electronics will be used. System modeling and experimentation have contributed to the development of the positioning system and results indicate that desired ETS performance is achievable.

  17. Ge and B doped collapsed photonic crystal optical fibre, a potential TLD material for low dose measurements

    NASA Astrophysics Data System (ADS)

    Rozaila, Z. Siti; Alyahyawi, Amjad; Khandaker, M. U.; Amin, Y. M.; Bradley, D. A.; Maah, M. J.

    2016-09-01

    Offering a number of advantageous features, tailor-made silica-based fibres are attracting attention as thermoluminesence (TL) dosimeters. We have performed a detailed study of the TL properties of Ge-doped and Ge-B-doped collapsed photonic crystal fibres (PCFc), most particularly with regard to their potential use for the environmental and X-ray diagnostic dose monitoring. Extrinsic doping and defects generated by strain at the fused inner walls of the collapsed fibres result in the PCFc-Ge-B and PCFc-Ge fibres producing markedly greater TL response than that of the phosphor-based dosimeter TLD-100, by some 9 and 7×, respectively. The linearity of TL yield has been investigated for X-ray doses from 0.5 mGy to 10 mGy. For a dose of 1 Gy, the energy response of the PCFs and TLD-100 has been studied using X-rays generated at accelerating potentials from 20 kVp through to 200 kVp and for the 1.25 MeV mean gamma-ray energy from 60Co. The effective atomic number , Zeffof PCFc-Ge and PCFc-Ge-B was estimated to be 12.5 and 14.4, respectively. Some 35 days post-irradiation, fading of the stored TL signal from PCFc-Ge-B and PCFc-Ge were found to be ∼15% and 20% respectively, with mean loss in TL emission of 0.4-0.5% per day. The present doped-silica collapsed PCFs provide greatly improved TLD performance compared to that of previous fibre designs and phosphor-based TLD-100.

  18. Identification of a Mutation Causing Deficient BMP1/mTLD Proteolytic Activity in Autosomal Recessive Osteogenesis Imperfecta

    PubMed Central

    Martínez-Glez, Víctor; Valencia, Maria; Caparrós-Martín, José A.; Aglan, Mona; Temtamy, Samia; Tenorio, Jair; Pulido, Veronica; Lindert, Uschi; Rohrbach, Marianne; Eyre, David; Giunta, Cecilia; Lapunzina, Pablo; Ruiz-Perez, Victor L.

    2013-01-01

    Herein, we have studied a consanguineous Egyptian family with two children diagnosed with severe autosomal recessive osteogenesis imperfecta (AR-OI) and a large umbilical hernia. Homozygosity mapping in this family showed lack of linkage to any of the previously known AR-OI genes, but revealed a 10.27 MB homozygous region on chromosome 8p in the two affected sibs, which comprised the procollagen I C-terminal propeptide (PICP) endopeptidase gene BMP1. Mutation analysis identified both patients with a Phe249Leu homozygous missense change within the BMP1 protease domain involving a residue, which is conserved in all members of the astacin group of metalloproteases. Type I procollagen analysis in supernatants from cultured fibroblasts demonstrated abnormal PICP processing in patient-derived cells consistent with the mutation causing decreased BMP1 function. This was further confirmed by overexpressing wild type and mutant BMP1 longer isoform (mammalian Tolloid protein [mTLD]) in NIH3T3 fibroblasts and human primary fibroblasts. While overproduction of normal mTLD resulted in a large proportion of proα1(I) in the culture media being C-terminally processed, proα1(I) cleavage was not enhanced by an excess of the mutant protein, proving that the Phe249Leu mutation leads to a BMP1/mTLD protein with deficient PICP proteolytic activity. We conclude that BMP1 is an additional gene mutated in AR-OI. PMID:22052668

  19. Precision and accuracy of 3D lower extremity residua measurement systems

    NASA Astrophysics Data System (ADS)

    Commean, Paul K.; Smith, Kirk E.; Vannier, Michael W.; Hildebolt, Charles F.; Pilgram, Thomas K.

    1996-04-01

    Accurate and reproducible geometric measurement of lower extremity residua is required for custom prosthetic socket design. We compared spiral x-ray computed tomography (SXCT) and 3D optical surface scanning (OSS) with caliper measurements and evaluated the precision and accuracy of each system. Spiral volumetric CT scanned surface and subsurface information was used to make external and internal measurements, and finite element models (FEMs). SXCT and OSS were used to measure lower limb residuum geometry of 13 below knee (BK) adult amputees. Six markers were placed on each subject's BK residuum and corresponding plaster casts and distance measurements were taken to determine precision and accuracy for each system. Solid models were created from spiral CT scan data sets with the prosthesis in situ under different loads using p-version finite element analysis (FEA). Tissue properties of the residuum were estimated iteratively and compared with values taken from the biomechanics literature. The OSS and SXCT measurements were precise within 1% in vivo and 0.5% on plaster casts, and accuracy was within 3.5% in vivo and 1% on plaster casts compared with caliper measures. Three-dimensional optical surface and SXCT imaging systems are feasible for capturing the comprehensive 3D surface geometry of BK residua, and provide distance measurements statistically equivalent to calipers. In addition, SXCT can readily distinguish internal soft tissue and bony structure of the residuum. FEM can be applied to determine tissue material properties interactively using inverse methods.

  20. Hydrogeomorphic response to extreme rainfall in headwater systems: Flash floods and debris flows

    NASA Astrophysics Data System (ADS)

    Borga, Marco; Stoffel, Markus; Marchi, Lorenzo; Marra, Francesco; Jakob, Matthias

    2014-10-01

    Flash floods and debris flows develop at space and time scales that conventional observation systems for rainfall, streamflow and sediment discharge are not able to monitor. Consequently, the atmospheric, hydrological and geomorphic controls on these hydrogeomorphic processes are poorly understood, leading to highly uncertain warning and risk management. On the other hand, remote sensing of precipitation and numerical weather predictions have become the basis of several flood forecasting systems, enabling increasingly accurate detection of hazardous events. The objective of this paper is to provide a review on current European and international research on early warning systems for flash floods and debris flows. We expand upon these themes by identifying: (a) the state of the art; (b) knowledge gaps; and (c) suggested research directions to advance warning capabilities for extreme hydrogeomorphic processes. We also suggest three areas in which advancements in science will have immediate and important practical consequence, namely development of rainfall estimation and nowcasting schemes suited to the specific space-time scales, consolidating physical, engineering and social datasets of flash floods and debris-flows, integration of methods for multiple hydrogeomorphic hazard warning.

  1. The Regional Hydrologic Extremes Assessment System: A software framework for hydrologic modeling and data assimilation.

    PubMed

    Andreadis, Konstantinos M; Das, Narendra; Stampoulis, Dimitrios; Ines, Amor; Fisher, Joshua B; Granger, Stephanie; Kawata, Jessie; Han, Eunjin; Behrangi, Ali

    2017-01-01

    The Regional Hydrologic Extremes Assessment System (RHEAS) is a prototype software framework for hydrologic modeling and data assimilation that automates the deployment of water resources nowcasting and forecasting applications. A spatially-enabled database is a key component of the software that can ingest a suite of satellite and model datasets while facilitating the interfacing with Geographic Information System (GIS) applications. The datasets ingested are obtained from numerous space-borne sensors and represent multiple components of the water cycle. The object-oriented design of the software allows for modularity and extensibility, showcased here with the coupling of the core hydrologic model with a crop growth model. RHEAS can exploit multi-threading to scale with increasing number of processors, while the database allows delivery of data products and associated uncertainty through a variety of GIS platforms. A set of three example implementations of RHEAS in the United States and Kenya are described to demonstrate the different features of the system in real-world applications.

  2. Susceptibility of South Korea to hydrologic extremes affecting the global food system

    NASA Astrophysics Data System (ADS)

    Puma, M. J.; Chon, S. Y.

    2015-12-01

    Food security in South Korea is closely linked to trade in the global food system. The country's production of major grains declined from 5.8 million metric tons (mmt) in 1998 to 4.8 mmt in 2014, which coincided with a shift in grain self sufficiency from 43% down to 24% over this same period. Many factors led to these changes, including reductions in domestic agricultural land, governmental policies supporting industry over agriculture, and a push towards trade liberalization. South Korea's self sufficiency is now one of the lowest among Organisation for Economic Co-operation and Development (OECD) countries, leaving it vulnerable to disruptions in the global food system. Here we explore this vulnerability by assessing how global trade disruptions would affect Korea's food security. We impose historical extreme drought and flood events that would possibly affect today's major food producing regions concurrently. Next we compute food supply deficits in South Korea that might result from these events. Our analyses provide a framework for formulating domestic food policies to enhance South Korea's food security in the increasingly fragile global food system.

  3. The Regional Hydrologic Extremes Assessment System: A software framework for hydrologic modeling and data assimilation

    PubMed Central

    Das, Narendra; Stampoulis, Dimitrios; Ines, Amor; Fisher, Joshua B.; Granger, Stephanie; Kawata, Jessie; Han, Eunjin; Behrangi, Ali

    2017-01-01

    The Regional Hydrologic Extremes Assessment System (RHEAS) is a prototype software framework for hydrologic modeling and data assimilation that automates the deployment of water resources nowcasting and forecasting applications. A spatially-enabled database is a key component of the software that can ingest a suite of satellite and model datasets while facilitating the interfacing with Geographic Information System (GIS) applications. The datasets ingested are obtained from numerous space-borne sensors and represent multiple components of the water cycle. The object-oriented design of the software allows for modularity and extensibility, showcased here with the coupling of the core hydrologic model with a crop growth model. RHEAS can exploit multi-threading to scale with increasing number of processors, while the database allows delivery of data products and associated uncertainty through a variety of GIS platforms. A set of three example implementations of RHEAS in the United States and Kenya are described to demonstrate the different features of the system in real-world applications. PMID:28545077

  4. A Real-Time Fatigue Monitoring and Analysis System for Lower Extremity Muscles with Cycling Movement

    PubMed Central

    Chen, Szi-Wen; Liaw, Jiunn-Woei; Chan, Hsiao-Lung; Chang, Ya-Ju; Ku, Chia-Hao

    2014-01-01

    A real-time muscle fatigue monitoring system was developed to quantitatively detect the muscle fatigue of subjects during cycling movement, where a fatigue progression measure (FPM) was built-in. During the cycling movement, the electromyogram (EMG) signals of the vastus lateralis and gastrocnemius muscles in one leg as well as cycling speed are synchronously measured in a real-time fashion. In addition, the heart rate (HR) and the Borg rating of perceived exertion scale value are recorded per minute. Using the EMG signals, the electrical activity and median frequency (MF) are calculated per cycle. Moreover, the updated FPM, based on the percentage of reduced MF counts during cycling movement, is calculated to measure the onset time and the progressive process of muscle fatigue. To demonstrate the performance of our system, five young healthy subjects were recruited. Each subject was asked to maintain a fixed speed of 60 RPM, as best he/she could, under a constant load during the pedaling. When the speed reached 20 RPM or the HR reached the maximal training HR, the experiment was then terminated immediately. The experimental results show that the proposed system may provide an on-line fatigue monitoring and analysis for the lower extremity muscles during cycling movement. PMID:25014101

  5. Fusion-Fission of Extremely Light Mass Compound Systems 20,21,22Ne*

    NASA Astrophysics Data System (ADS)

    Singh, BirBikram; Kaur, Manpreet; Gupta, Raj K.

    The study of binary symmetric decay (BSD) of extremely light compound systems 20,21,22Ne*, formed in 10,11B + 10,11B reactions at Elab = 48 MeV, is extended to analyze the effects of orientation degree of freedom within the framework of Dynamical Cluster-decay Model (DCM) of Gupta and collaborators. As observed in one of our earlier study with spherical consideration of nuclei, the present one also reveals the occurrence of the fusion-fission (ff) in the BSD of these compound systems, which is in competition with the deep inelastic orbiting (DIO), having maximum contribution for 20Ne* followed by 21Ne* and 22Ne*, in line with experimental results. The comparison between the BSD cross-sections, σBSD, of compound systems 20,21,22Ne* for the considerations of spherical and oriented nuclei, shows similar results with the exception that the contribution of ff is largest in the decay of 20Ne* for the later case. Also, the difference of the values of neck length parameter ΔR are more for the case of oriented nuclei. The agreement with the experimental data is good for both the considerations.

  6. [Effects of extremely high-frequency electromagnetic radiation on the immune system and systemic regulation of homeostasis].

    PubMed

    Lushnikov, K V; Gapeev, A B; Chemeris, N K

    2002-01-01

    Low-intensity of electromagnetic radiation of extremely high frequencies (EHF EMR) is effectively used in medical practice for diagnostics, prevention and treatment of a broad spectrum of diseases of different etiology. However, in spite of existence of many hypotheses about mechanisms of EHF EMR effects on the molecular and cellular levels of organization of living systems, there is not conception that could explain all diversity of the EHF-therapy effects from unified approach. In our opinion, the problem of determination of mechanisms of EHF EMR effects on living organism is divided into two basic tasks: first, determining subcellular structures which can receive radiation, and, second, studying physiological reactions of the organism which are caused by radiation. It is obviously, that investigation of functions of single cells and subcellular elements can not entirely explain therapeutic effects and mechanisms of EHF EMR influence on multicellular organism on the whole. Plenty of functional relationships between organs and systems of organs should be taken into account. In the present review, a realization of the EHF-therapy effects due to the influence on immune system functions and start of system mechanisms of maintenance of the homeostasis on the organism level is hypothesized. Potential targets for EHF EMR acception on the level of different systems of the organism are analysed. The material is formed so that functional relations between immune system and other regulatory systems (nervous and endocrine systems) are traced.

  7. Measurement of Thyroid Dose by TLD arising from Radiotherapy of Breast Cancer Patients from Supraclavicular Field.

    PubMed

    Farhood, B; Bahreyni Toossi, M T; Vosoughi, H; Khademi, S; Knaup, C

    2016-09-01

    Breast cancer is the most frequently diagnosed cancer and the leading global cause of cancer death among women worldwide. Radiotherapy plays a significant role in treatment of breast cancer and reduces locoregional recurrence and eventually improves survival. The treatment fields applied for breast cancer treatment include: tangential, axillary, supraclavicular and internal mammary fields. In the present study, due to the presence of sensitive organ such as thyroid inside the supraclavicular field, thyroid dose and its effective factors were investigated. Thyroid dose of 31 female patients of breast cancer with involved supraclavicular lymph nodes which had undergone radiotherapy were measured. For each patient, three TLD-100 chips were placed on their thyroid gland surface, and thyroid doses of patients were measured. The variables of the study include shield shape, the time of patient's setup, the technologists' experience and qualification. Finally, the results were analyzed by ANOVA test using SPSS 11.5 software. The average age of the patients was 46±10 years. The average of thyroid dose of the patients was 140±45 mGy (ranged 288.2 and 80.8) in single fraction. There was a significant relationship between the thyroid dose and shield shape. There was also a significant relationship between the thyroid dose and the patient's setup time. Beside organ at risk such as thyroid which is in the supraclavicular field, thyroid dose possibility should be reduced. For solving this problem, an appropriate shield shape, the appropriate time of the patient's setup, etc. could be considered.

  8. Reproducibility study of TLD-100 micro-cubes at radiotherapy dose level.

    PubMed

    da Rosa, L A; Regulla, D F; Fill, U A

    1999-03-01

    The precision of the thermoluminescent response of Harshaw micro-cube dosimeters (TLD-100), evaluated in both Harshaw thermoluminescent readers 5500 and 3500, for 1 Gy dose value, was investigated. The mean reproducibility for micro-cubes, pre-readout annealed at 100 degrees C for 15 min, evaluated with the manual planchet reader 3500, is 0.61% (1 standard deviation). When micro-cubes are evaluated with the automated hot-gas reader 5500, reproducibility values are undoubtedly worse, mean reproducibility for numerically stabilised dosimeters being equal to 3.27% (1 standard deviation). These results indicate that the reader model 5500, or, at least, the instrument used for the present measurements, is not adequate for micro-cube evaluation, if precise and accurate dosimetry is required. The difference in precision is apparently due to geometry inconsistencies in the orientation of the imperfect micro-cube faces during readout, requiring careful and manual reproducible arrangement of the selected micro-cube faces in contact with the manual reader planchet.

  9. Patient Reported Outcomes Measurement Information System (PROMIS) in the upper extremity: the future of outcomes reporting?

    PubMed

    Makhni, Eric C; Meadows, Molly; Hamamoto, Jason T; Higgins, John D; Romeo, Anthony A; Verma, Nikhil N

    2017-02-01

    Patient reported outcomes (PROs) serve an integral role in clinical research by helping to determine the impact of clinical care as experienced by the patient. With recent initiatives in health care policy and pay for performance, outcome reporting is now recognized as a policy-driven requirement in addition to a clinical research tool. For outcome measures to satisfy these regulatory requirements and provide value in understanding disease outcomes, they must be responsive and efficient. Recent research has uncovered certain concerns regarding traditional PROs in patients with upper extremity disability and injury. These include lack of consensus regarding selection of PROs for a given diagnoses, inconsistent techniques of administration of the same PROs, and the administrative burden to patients and providers of completing these forms. To address these limitations, emphasis has been placed on streamlining the outcomes reporting process, and, as a result, the National Institutes of Health (NIH) created the Patient Reported Outcomes Measurement Information System (PROMIS). PROMIS forms were created to comprehensively and efficiently measure outcomes across multiple disease states, including orthopedics. These tools exist in computer adaptive testing and short forms with the intention of more efficiently measuring outcomes compared with legacy PROs. The goals of this review are to highlight the main components of PROMIS reporting tools and identify recent use of the scores in the upper extremity literature. The review will also highlight the research and health policy potentials and limitations of implementing PROMIS into everyday orthopedic practice. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  10. A computer aided diagnosis system for thyroid disease using extreme learning machine.

    PubMed

    Li, Li-Na; Ouyang, Ji-Hong; Chen, Hui-Ling; Liu, Da-You

    2012-10-01

    In this paper, we present an effective and efficient computer aided diagnosis (CAD) system based on principle component analysis (PCA) and extreme learning machine (ELM) to assist the task of thyroid disease diagnosis. The CAD system is comprised of three stages. Focusing on dimension reduction, the first stage applies PCA to construct the most discriminative new feature set. After then, the system switches to the second stage whose target is model construction. ELM classifier is explored to train an optimal predictive model whose parameters are optimized. As we known, the number of hidden neurons has an important role in the performance of ELM, so we propose an experimental method to hunt for the optimal value. Finally, the obtained optimal ELM model proceeds to perform the thyroid disease diagnosis tasks using the most discriminative new feature set and the optimal parameters. The effectiveness of the resultant CAD system (PCA-ELM) has been rigorously estimated on a thyroid disease dataset which is taken from UCI machine learning repository. We compare it with other related methods in terms of their classification accuracy. Experimental results demonstrate that PCA-ELM outperforms other ones reported so far by 10-fold cross-validation method, with the mean accuracy of 97.73% and with the maximum accuracy of 98.1%. Besides, PCA-ELM performs much faster than support vector machines (SVM) based CAD system. Consequently, the proposed method PCA-ELM can be considered as a new powerful tools for diagnosing thyroid disease with excellent performance and less time.

  11. HPC Colony II: FAST_OS II: Operating Systems and Runtime Systems at Extreme Scale

    SciTech Connect

    Moreira, Jose

    2013-11-13

    HPC Colony II has been a 36-month project focused on providing portable performance for leadership class machines—a task made difficult by the emerging variety of more complex computer architectures. The project attempts to move the burden of portable performance to adaptive system software, thereby allowing domain scientists to concentrate on their field rather than the fine details of a new leadership class machine. To accomplish our goals, we focused on adding intelligence into the system software stack. Our revised components include: new techniques to address OS jitter; new techniques to dynamically address load imbalances; new techniques to map resources according to architectural subtleties and application dynamic behavior; new techniques to dramatically improve the performance of checkpoint-restart; and new techniques to address membership service issues at scale.

  12. A newly designed experimental system for exposure of mammalian cells to extremely low frequency magnetic fields.

    PubMed

    Miyakoshi, J; Ohtsu, S; Tatsumi-Miyajima, J; Takebe, H

    1994-03-01

    To examine the biological effects of extremely low frequency magnetic field (ELFMF), we have designed and manufactured a new equipment for long-term and high-density exposure of cells to ELFMF. The ELFMF exposure system consists of a generator of magnets with a built-in CO2 incubator, an alternating current (AC) power supply, a gas compressor and a thermocontroller for the incubator, and a cooling unit for the magnets. The CO2 incubator made of acrylic resin is inserted into the inner-space of the silicon steel strip-cores. In this system, the temperature of the incubator is maintained at 37 +/- 0.5 degrees C. The maximum magnetic flux density on the exposure area of the incubator is 500 mT (T; tesla) at a current of 556 Arms (rms; root mean square) at 50 Hz. The long-term (up to 120 hr) exposure of 400 mT ELFMF did not affect the growth of both HL60RG and CCRF-CEM cells originated from human leukemia. The post-X-irradiation exposure of 400 mT ELFMF for 2 hr also did not affect the radiation sensitivity of GM0637 and TAT2SF cells originated from a normal human and an ataxia telangiectasia patient.

  13. Similarities between extreme events in the solar-terrestrial system by means of nonextensivity

    NASA Astrophysics Data System (ADS)

    Balasis, G.; Papadimitriou, C.; Daglis, I. A.; Anastasiadis, A.; Sandberg, I.; Eftaxias, K.

    2011-09-01

    The dynamics of complex systems are founded on universal principles that can be used to describe disparate problems ranging from particle physics to economies of societies. A corollary is that transferring ideas and results from investigators in hitherto disparate areas will cross-fertilize and lead to important new results. In this contribution, we investigate the existence of a universal behavior, if any, in solar flares, magnetic storms, earthquakes and pre-seismic electromagnetic (EM) emissions, extending the work recently published by Balasis et al. (2011a). A common characteristic in the dynamics of the above-mentioned phenomena is that their energy release is basically fragmentary, i.e. the associated events are being composed of elementary building blocks. By analogy with earthquakes, the magnitude of the magnetic storms, solar flares and pre-seismic EM emissions can be appropriately defined. Then the key question we can ask in the frame of complexity is whether the magnitude distribution of earthquakes, magnetic storms, solar flares and pre-fracture EM emissions obeys the same law. We show that these apparently different extreme events, which occur in the solar-terrestrial system, follow the same energy distribution function. The latter was originally derived for earthquake dynamics in the framework of nonextensive Tsallis statistics.

  14. Prognostic scoring system for peripheral nerve repair in the upper extremity.

    PubMed

    Galanakos, Spyridon P; Zoubos, Aristides B; Mourouzis, Iordanis; Ignatiadis, Ioannis; Bot, Arjan G J; Soucacos, Panayotis N

    2013-02-01

    So far, predictive models with individualized estimates of prognosis for patients with peripheral nerve injuries are lacking. Our group has previously shown the prognostic value of a standardized scoring system by examining the functional outcome after acute, sharp complete laceration and repair of median and/or ulnar nerves at various levels in the forearm. In the present study, we further explore the potential mathematical model in order to devise an effective prognostic scoring system. We retrospectively collected medical record data of 73 cases with a peripheral nerve injury in the upper extremity in order to estimate which patients would return to work, and what time was necessary to return to the pre-injury work. Postoperative assessment followed the protocol described by Rosén and Lundborg. We found that return to pre-injury work can be predicted with high sensitivity (100%) and specificity (95%) using the total numerical score of the Rosén and Lundborg protocol at the third follow-up interval (TS3) as well as the difference between the TS3 and the total score at second follow-up interval (TS2). In addition, the factors age and type of injured nerve (median, ulnar, or combined) can determine the time of return to work based on a mathematical model. This prognostic protocol can be a useful tool to provide information about the functional and social prospects of the patients with these types of injuries.

  15. ExM:System Support for Extreme-Scale, Many-Task Applications

    SciTech Connect

    Katz, Daniel S

    2011-05-31

    The ever-increasing power of supercomputer systems is both driving and enabling the emergence of new problem-solving methods that require the effi cient execution of many concurrent and interacting tasks. Methodologies such as rational design (e.g., in materials science), uncertainty quanti fication (e.g., in engineering), parameter estimation (e.g., for chemical and nuclear potential functions, and in economic energy systems modeling), massive dynamic graph pruning (e.g., in phylogenetic searches), Monte-Carlo- based iterative fi xing (e.g., in protein structure prediction), and inverse modeling (e.g., in reservoir simulation) all have these requirements. These many-task applications frequently have aggregate computing needs that demand the fastest computers. For example, proposed next-generation climate model ensemble studies will involve 1,000 or more runs, each requiring 10,000 cores for a week, to characterize model sensitivity to initial condition and parameter uncertainty. The goal of the ExM project is to achieve the technical advances required to execute such many-task applications efficiently, reliably, and easily on petascale and exascale computers. In this way, we will open up extreme-scale computing to new problem solving methods and application classes. In this document, we report on combined technical progress of the collaborative ExM project, and the institutional financial status of the portion of the project at University of Chicago, over the rst 8 months (through April 30, 2011)

  16. Risk-Cost Estimation of On-Site Wastewater Treatment System Failures Using Extreme Value Analysis.

    PubMed

    Kohler, Laura E; Silverstein, JoAnn; Rajagopalan, Balaji

    2017-05-01

      Owner resistance to increasing regulation of on-site wastewater treatment systems (OWTS), including obligatory inspections and upgrades, moratoriums and cease-and-desist orders in communities around the U.S. demonstrate the challenges associated with managing risks of inadequate performance of owner-operated wastewater treatment systems. As a result, determining appropriate and enforceable performance measures in an industry with little history of these requirements is challenging. To better support such measures, we develop a statistical method to predict lifetime failure risks, expressed as costs, in order to identify operational factors associated with costly repairs and replacement. A binomial logistic regression is used to fit data from public records of reported OWTS failures, in Boulder County, Colorado, which has 14 300 OWTS to determine the probability that an OWTS will be in a low- or high-risk category for lifetime repair and replacement costs. High-performing or low risk OWTS with repairs and replacements below the threshold of $9000 over a 40-year life are associated with more frequent inspections and upgrades following home additions. OWTS with a high risk of exceeding the repair cost threshold of $18 000 are further analyzed in a variation of extreme value analysis (EVA), Points Over Threshold (POT) where the distribution of risk-cost exceedance values are represented by a generalized Pareto distribution. The resulting threshold cost exceedance estimates for OWTS in the high-risk category over a 40-year expected life ranged from $18 000 to $44 000.

  17. Extremely hypotrophic newborn of mother with systemic lupus erythematosus and antiphospholipid syndrome.

    PubMed

    Mockova, A; Dortova, E; Dort, J; Nahlovsky, J; Korecko, V; Ulcova-Gallova, Z

    2014-03-01

    The case presented describes a high-risk pregnancy of a woman with systemic lupus erythematosus (SLE) with multiple lesions of central nervous system (CNS), vasculitis, secondary epilepsy and antiphospholipid syndrome (APS). At gestational age 28 weeks and 3 days the pregnancy was urgently terminated via caesarean section and an extremely hypotrophic immature newborn with a birth weight of 580 g was born. The high disease activity in the mother at the time of conception and the histologically proven chronic placental insufficiency due to APS are presumably the causes for the extensive hypotrophy of the neonate. The significant comorbidity of the newborn, including respiratory distress syndrome, bronchopulmonary dysplasia, necrotizing enterocolitis, osteopathy of prematurity, transient hypothyroidism and hypocortisolism, vesicoureteral reflux, and hypertonic-hyperexcitation syndrome complicated his three-month stay in NICU. A positive titre of transplacentally transferred anticardiolipin and anti-β2 glycoprotein antibody was detected in the child and persisted through the following 30 months. During the three-year follow-up, significantly delayed neuropsychological development with microcephaly (-4 SD) and short stature of the child was observed. Finally, the authors discuss possible causes of neuropsychological consequences in children of mothers with SLE and APS and emphasize the need for long-term monitoring and specialized care to improve development of these children.

  18. Implementing extreme weather event advice and guidance in English public health systems.

    PubMed

    Wistow, Jonathan; Curtis, Sarah; Bone, Angie

    2017-09-01

    Extreme weather events (EWEs) can significantly impact on mortality and morbidity in the UK. How EWE guidance is disseminated and applied across health and social care systems, at the local, operational level, is not well understood. This exploratory study develops tools and resources to assist local stakeholders to cascade national 'all weather' EWE guidance across local systems. These resources are also used to evaluate the local interpretation and implementation of this advice and guidance within three local authority areas. In total, five discussion group meetings were held and 45 practitioners took part in the study. A thematic analysis was conducted. The main themes emerging from the analysis related to awareness of PHE guidance for EWE preparedness, data sharing feasibility, community engagement, specific conditions in remote rural areas and capacity of frontline staff. The relative difficulty in finding where the study 'best fits' on local stakeholders' agendas suggests that year-round and preparedness planning for EWEs may not have been considered a high priority in participating areas. This study adds to the relatively limited evidence internationally concerning the practical implementation at local level of national adaptation advice and guidance and potential barriers to achieving this.

  19. Extremely Low Frequency Electromagnetic Field from Convective Air Warming System on Temperature Selection and Distance.

    PubMed

    Cho, Kwang Rae; Kim, Myoung-Hun; Ko, Myoung Jin; Jung, Jae Wook; Lee, Ki Hwa; Park, Yei-Heum; Kim, Yong Han; Kim, Ki Hoon; Kim, Jin Soo

    2014-12-01

    Hypothermia generates potentially severe complications in operating or recovery room. Forced air warmer is effective to maintain body temperature. Extremely low frequency electromagnetic field (ELF-EMF) is harmful to human body and mainly produced by electronic equipment including convective air warming system. We investigated ELF-EMF from convective air warming device on various temperature selection and distance for guideline to protect medical personnel and patients. The intensity of ELF-EMF was measured as two-second interval for five minutes on various distance (0.1, 0.2, 0.3, 0.5 and 1meter) and temperature selection (high, medium, low and ambient). All of electrical devices were off including lamp, computer and air conditioner. Groups were compared using one-way ANOVA. P<0.05 was considered significant. Mean values of ELF-EMF on the distance of 30 cm were 18.63, 18.44, 18.23 and 17.92 milligauss (mG) respectively (high, medium, low and ambient temperature set). ELF-EMF of high temperature set was higher than data of medium, low and ambient set in all the distances. ELF-EMF from convective air warming system is higher in condition of more close location and higher temperature. ELF-EMF within thirty centimeters exceeds 2mG recommended by Swedish TCO guideline.

  20. Groundwater artificial recharge solutions for integrated management of watersheds and aquifer systems under extreme drought scenarios

    NASA Astrophysics Data System (ADS)

    Lobo-Ferreira, Joao-Paulo; Oliveira, Luís.; Diamantino, Catarina

    2010-05-01

    The paper addresses groundwater artificial recharge solutions for integrated management of watersheds and aquifer systems under extreme drought scenarios. The conceptual idea of Aquifer Storage and Recovery (ASR) is considered as one of the scientific based solutions towards scientific based mitigation measures to climate variability and change in many parts of the world. In Portugal two European Union sponsored 6th Framework Programme for Research Projects have been addressing this topic, namely GABARDINE Project on "Groundwater artificial recharge based on alternative sources of water: Advanced integrated technologies and management" and the Coordinated Action ASEMWATERNet, a "Multi-Stakeholder Platform for ASEM S&T Cooperation on Sustainable Water Use". An application of Aquifer Storage and Recovery methodologies aiming drought mitigation and Integrated Water Resource Management of the Algarve (Portugal). The technique of artificial recharge of groundwater is used in many parts of the world with several aims, e.g. water storing in appropriate aquifers for the mitigation of future water needs during droughts or as protection against pollution or even for the recovery of groundwater quality. Artificial recharge of the aquifer systems of Campina de Faro and Silves-Querença is addressed in this paper, proposed to be an alternative to decrease the vulnerability of the Algarve to a future drought. Integrated management of water resources in the Algarve is not a clear issue since the last decade, when groundwater resources that supplied almost all water needs, have been drastically replaced by surface water stored in new reservoirs.

  1. Sequential Nonlinear Learning for Distributed Multiagent Systems via Extreme Learning Machines.

    PubMed

    Vanli, Nuri Denizcan; Sayin, Muhammed O; Delibalta, Ibrahim; Kozat, Suleyman Serdar

    2017-03-01

    We study online nonlinear learning over distributed multiagent systems, where each agent employs a single hidden layer feedforward neural network (SLFN) structure to sequentially minimize arbitrary loss functions. In particular, each agent trains its own SLFN using only the data that is revealed to itself. On the other hand, the aim of the multiagent system is to train the SLFN at each agent as well as the optimal centralized batch SLFN that has access to all the data, by exchanging information between neighboring agents. We address this problem by introducing a distributed subgradient-based extreme learning machine algorithm. The proposed algorithm provides guaranteed upper bounds on the performance of the SLFN at each agent and shows that each of these individual SLFNs asymptotically achieves the performance of the optimal centralized batch SLFN. Our performance guarantees explicitly distinguish the effects of data- and network-dependent parameters on the convergence rate of the proposed algorithm. The experimental results illustrate that the proposed algorithm achieves the oracle performance significantly faster than the state-of-the-art methods in the machine learning and signal processing literature. Hence, the proposed method is highly appealing for the applications involving big data.

  2. Multilayer coated optics for an alpha-class extreme ultraviolet lithography system

    SciTech Connect

    Folta, J A; Grabner, R F; Hudyma, R M; Montcalm, C; Schmidt, M A; Spiller, E; Walton, C C; Wedowski, M

    1999-08-25

    We present the results of coating the first set of optical elements for an alpha-class extreme-ultraviolet (EUV) lithography system, the Engineering Test Stand (ETS). The optics were coated with Mo/Si multilayer mirrors using an upgraded DC-magnetron sputtering system. Characterization of the near-normal incidence EUV reflectance was performed using synchrotron radiation from the Advanced Light Source at the Lawrence Berkeley National Laboratory. Stringent requirements were met for these multilayer coatings in terms of reflectance, wavelength matching among the different optics, and thickness control across the diameter of each individual optic. Reflectances above 65% were achieved at 13.35 nm at near-normal angles of incidence. The run-to-run reproducibility of the reflectance peak wavelength was maintained to within 0.4%, providing the required wavelength matching among the seven multilayer-coated optics. The thickness uniformity (or gradient) was controlled to within {+-}0.25% peak-to-valley (P-V) for the condenser optics and {+-}0.1% P-V for the four projection optics, exceeding the prescribed specification for the optics of the ETS.

  3. An evaluation of a coupled atmosphere-ocean modelling system for regional climate studies: extreme events in the North Atlantic

    NASA Astrophysics Data System (ADS)

    Mooney, Priscilla A.; Mulligan, Frank J.

    2013-04-01

    We investigate the ability of a coupled regional atmosphere-ocean modelling system to simulate two extreme events in the North Atlantic. In this study we use the Coupled-Ocean-Atmosphere-Wave-Sediment Transport (COAWST; Warner et al.) modelling system with only the atmosphere and ocean models activated. COAWST couples the atmosphere model (Weather Research and Forecasting model; WRF) to the ocean model (Regional Ocean Modelling System; ROMS) with the Model Coupling Toolkit. Results from the coupled system are compared with atmosphere only simulations of North Atlantic storms to evaluate the performance of the coupled modelling system. Two extreme events (Hurricane Katia and Hurricane Irene) were chosen to assess the level of improvement (or otherwise) arising from coupling WRF with ROMS. These two hurricanes involve different dynamics and present different challenges to the modeling system. This provides a robust assessment of the advantages or disadvantages of coupling WRF with ROMS for regional climate modelling studies of extreme events in the North Atlantic. We examine the ability of the coupled modelling system to simulate these two extreme events by comparing modelled storm tracks, storm intensities, wind speeds and sea surface temperatures with observations in all cases. The effect of domain size, and two different planetary boundary layers used in WRF are also reported.

  4. Impact of the extreme 2009 wildfires in Victoria on the soil system and implications for fire behaviour

    NASA Astrophysics Data System (ADS)

    Doerr, Stefan; Shakesby, R. A.; Sheridan, G. J.; Lane, P. N. J.; Smith, H. G.; Bell, T.; Brooks, J.; Blake, W. H.

    2010-05-01

    The recent catastrophic wildfires near Melbourne in 2009 occurred during unprecedented extreme fire weather when dry northerly winds gusting up to 100 km/h coincided with the highest temperatures ever recorded in this region. These conditions, combined with the very high biomass of mature eucalypt forests (estimated to exceed 40 t/ha in places), very low fuel moisture conditions and steep slopes, generated extreme burning conditions. A rapid response project, funded by the NERC Urgency scheme, was launched to reconstruct heat input into the soils, and to determine associated effects on soil properties and seed bank survival. Three replicate sites were sampled for extremely high burn severity and high burn severity, and four for long unburnt control terrain, within mature mixed-species eucalypt forests near Marysville in April 2009. Additional exploratory sampling was carried out in 'rainforest'. Ash (where applicable) and surface soil (0-2.5 cm and 2.5-5 cm) were collected at 20 sample grid points at each site. Here we report on preliminary outcomes from soil water repellency determination, and seedbank germination experiments, which allow reconstructing of soil temperature and burn severity, and provide insights into fire behaviour, of this extreme event. Field and laboratory assessment of the soil suggest that the heat input to the soil was less than might be supposed given the extreme estimated fire intensity (>70,000 kW/m). Our data indicate that soil temperatures in the top 0-2.5 cm did not exceed ca 200°C. The limited heat input into the soil stands in stark contrast to the extreme fire intensity. We speculate that it resulted from an unusually fast-moving fire front associated with the extreme wind speeds, causing a short fire residence time. Whilst this fire event has been extreme in many respects, its impact on the soil system has clearly been less than what might have been expected. Thus it could be argued that the more extreme burning conditions that

  5. ASAS J083241+2332.4: A NEW EXTREME LOW MASS RATIO OVERCONTACT BINARY SYSTEM

    SciTech Connect

    Sriram, K.; Malu, S.; Vivekananda Rao, P.; Choi, C. S.

    2016-03-15

    We present the R- and V-band CCD photometry and Hα line studies of an overcontact binary ASAS J083241+2332.4. The light curves exhibit totality along with a trace of the O’Connell effect. The photometric solution indicates that this system falls into the category of extreme low-mass ratio overcontact binaries with a mass ratio, q ∼ 0.06. Although a trace of the O’ Connell effect is observed, constancy of the Hα line along various phases suggest that a relatively higher magnetic activity is needed for it to show a prominent fill-in effect. The study of O–C variations reveals that the period of the binary shows a secular increase at the rate of dP/dt ∼ 0.0765 s years{sup −1}, which is superimposed by a low, but significant, sinusoidal modulation with a period of ∼8.25 years. Assuming that the sinusoidal variation is due to the presence of a third body, orbital elements have been derived. There exist three other similar systems, SX Crv, V857 Her, and E53, which have extremely low mass ratios and we conclude that ASAS J083241+2332.4 resembles SX Crv in many respects. Theoretical studies indicate that at a critical mass ratio range, q{sub critical} = 0.07–0.09, overcontact binaries should merge and form a fast rotating star, but it has been suggested that q{sub critical} can continue to fall up to 0.05 depending on the primary's mass and structure. Moreover, the obtained fill-out factors (50%–70%) indicate that mass loss is considerable and hydrodynamical simulations advocate that mass loss from L{sub 2} is mandatory for a successful merging process. Comprehensively, the results indicate that ASAS J083241+2332.4 is at a stage of merger. The pivotal role played by the subtle nature of the derived mass ratio in forming a rapidly rotating star has been discussed.

  6. Scientific drilling and the evolution of the earth system: climate, biota, biogeochemistry and extreme systems

    NASA Astrophysics Data System (ADS)

    Soreghan, G. S.; Cohen, A. S.

    2013-11-01

    A US National Science Foundation-funded workshop occurred 17-19 May 2013 at the University of Oklahoma to stimulate research using continental scientific drilling to explore earth's sedimentary, paleobiological and biogeochemical record. Participants submitted 3-page "pre-proposals" to highlight projects that envisioned using drill-core studies to address scientific issues in paleobiology, paleoclimatology, stratigraphy and biogeochemistry, and to identify locations where key questions can best be addressed. The workshop was also intended to encourage US scientists to take advantage of the exceptional capacity of unweathered, continuous core records to answer important questions in the history of earth's sedimentary, biogeochemical and paleobiologic systems. Introductory talks on drilling and coring methods, plus best practices in core handling and curation, opened the workshop to enable all to understand the opportunities and challenges presented by scientific drilling. Participants worked in thematic breakout sessions to consider questions to be addressed using drill cores related to glacial-interglacial and icehouse-greenhouse transitions, records of evolutionary events and extinctions, records of major biogeochemical events in the oceans, reorganization of earth's atmosphere, Lagerstätte and exceptional fossil biota, records of vegetation-landscape change, and special sampling requirements, contamination, and coring tool concerns for paleobiology, geochemistry, geochronology, and stratigraphy-sedimentology studies. Closing discussions at the workshop focused on the role drilling can play in studying overarching science questions about the evolution of the earth system. The key theme, holding the most impact in terms of societal relevance, is understanding how climate transitions have driven biotic change, and the role of pristine, stratigraphically continuous cores in advancing our understanding of this linkage. Scientific drilling, and particularly drilling

  7. Functionally interpretable local coordinate systems for the upper extremity using inertial & magnetic measurement systems.

    PubMed

    de Vries, W H K; Veeger, H E J; Cutti, A G; Baten, C; van der Helm, F C T

    2010-07-20

    Inertial Magnetic Measurement Systems (IMMS) are becoming increasingly popular by allowing for measurements outside the motion laboratory. The latest models enable long term, accurate measurement of segment motion in terms of joint angles, if initial segment orientations can accurately be determined. The standard procedure for definition of segmental orientation is based on the measurement of positions of bony landmarks (BLM). However, IMMS do not deliver position information, so an alternative method to establish IMMS based, anatomically understandable segment orientations is proposed. For five subjects, IMMS recordings were collected in a standard anatomical position for definition of static axes, and during a series of standardized motions for the estimation of kinematic axes of rotation. For all axes, the intra- and inter-individual dispersion was estimated. Subsequently, local coordinate systems (LCS) were constructed on the basis of the combination of IMMS axes with the lowest dispersion and compared with BLM based LCS. The repeatability of the method appeared to be high; for every segment at least two axes could be determined with a dispersion of at most 3.8 degrees. Comparison of IMMS based with BLM based LCS yielded compatible results for the thorax, but less compatible results for the humerus, forearm and hand, where differences in orientation rose to 17.2 degrees. Although different from the 'gold standard' BLM based LCS, IMMS based LCS can be constructed repeatable, enabling the estimation of segment orientations outside the laboratory. A procedure for the definition of local reference frames using IMMS is proposed. 2010 Elsevier Ltd. All rights reserved.

  8. Numerical implementation of time-dependent density functional theory for extended systems in extreme environments

    SciTech Connect

    Baczewski, Andrew David; Shulenburger, Luke; Desjarlais, Michael Paul; Magyar, Rudolph J.

    2014-02-01

    In recent years, DFT-MD has been shown to be a useful computational tool for exploring the properties of WDM. These calculations achieve excellent agreement with shock compression experiments, which probe the thermodynamic parameters of the Hugoniot state. New X-ray Thomson Scattering diagnostics promise to deliver independent measurements of electronic density and temperature, as well as structural information in shocked systems. However, they require the development of new levels of theory for computing the associated observables within a DFT framework. The experimentally observable x-ray scattering cross section is related to the electronic density-density response function, which is obtainable using TDDFT - a formally exact extension of conventional DFT that describes electron dynamics and excited states. In order to develop a capability for modeling XRTS data and, more generally, to establish a predictive capability for rst principles simulations of matter in extreme conditions, real-time TDDFT with Ehrenfest dynamics has been implemented in an existing PAW code for DFT-MD calculations. The purpose of this report is to record implementation details and benchmarks as the project advances from software development to delivering novel scienti c results. Results range from tests that establish the accuracy, e ciency, and scalability of our implementation, to calculations that are veri ed against accepted results in the literature. Aside from the primary XRTS goal, we identify other more general areas where this new capability will be useful, including stopping power calculations and electron-ion equilibration.

  9. An Automated System for Skeletal Maturity Assessment by Extreme Learning Machines.

    PubMed

    Mansourvar, Marjan; Shamshirband, Shahaboddin; Raj, Ram Gopal; Gunalan, Roshan; Mazinani, Iman

    2015-01-01

    Assessing skeletal age is a subjective and tedious examination process. Hence, automated assessment methods have been developed to replace manual evaluation in medical applications. In this study, a new fully automated method based on content-based image retrieval and using extreme learning machines (ELM) is designed and adapted to assess skeletal maturity. The main novelty of this approach is it overcomes the segmentation problem as suffered by existing systems. The estimation results of ELM models are compared with those of genetic programming (GP) and artificial neural networks (ANNs) models. The experimental results signify improvement in assessment accuracy over GP and ANN, while generalization capability is possible with the ELM approach. Moreover, the results are indicated that the ELM model developed can be used confidently in further work on formulating novel models of skeletal age assessment strategies. According to the experimental results, the new presented method has the capacity to learn many hundreds of times faster than traditional learning methods and it has sufficient overall performance in many aspects. It has conclusively been found that applying ELM is particularly promising as an alternative method for evaluating skeletal age.

  10. ELF (Extremely Low Frequency) communications system ecological monitoring program: Slime mold studies

    NASA Astrophysics Data System (ADS)

    Goodman, Eugene; Greenebaum, Ben

    1990-01-01

    It was previously shown that continuous exposure of the slime mold Physarum polycephalum to extremely low frequency (ELF) electromagnetic fields (EMF) simulating those generated by the Navy's ELF communication system (then Project Sanguine) could depress the rate of respiration, and lengthen the mitotic cell cycle. In a series of experiments beginning in 1981 and ending in 1987, it was determined that whether exposing Physarum to the field environment around the Wisconsin Transmitting Facility (WTF) could induce an altered physiological state. A laboratory component was also included to help verify methodology and to supplement studies performed at the WTF. Initially, the experimental effort was directed to devising methods to maintain axenic Physarum cultures under ambient environmental conditions. This involved using growth chambers that admit the electric field or current density from the surrounding environment; the cultures were returned to the laboratory for analysis. The successful methods placed the organism on an agar bed inside double containment and introduced the samples to be assayed into shaken liquid culture medium upon arrival at the laboratory. Both WTF-generated electromagnetic fields and background strengths were measured with the help of IITRI at study locations near the antenna, at the west ground of the WTF antenna, as well as at control sites.

  11. Tomographic control for wide field AO systems on extremely large telescopes

    NASA Astrophysics Data System (ADS)

    Petit, C.; Conan, J.-M.; Fusco, T.; Neichel, B.

    2010-07-01

    We investigate in this article tomographic control using both Laser and Natural Guide Stars (LGS and NGS) in the particular framework of the European Extremely Large Telescope (E-ELT) Wide Field Adaptive Optics (WFAO) modules design. A similar global control strategy has been indeed derived for both the Laser Tomographic Adaptive Optics (LTAO) and Multi-Conjugate Adaptive Optics (MCAO) modules of the E-ELT, due to similar constraints. This control strategy leads in both cases to a split control of low order modes measured thanks to NGS and high order modes measured thanks to LGS. We investigate here this split tomographic control, compared to an optimal coupled solution. To support our analysis, a dedicated simulation code has been developed. Indeed, due to the huge complexity of the EELT, fast simulation tools must be considered to explore quickly the tomographic issues. We describe our control strategy which has lead to considering split tomographic control. First results on Tomography for E-ELT WFAO systems are then presented and discussed.

  12. An Automated System for Skeletal Maturity Assessment by Extreme Learning Machines

    PubMed Central

    Mansourvar, Marjan; Shamshirband, Shahaboddin; Raj, Ram Gopal; Gunalan, Roshan; Mazinani, Iman

    2015-01-01

    Assessing skeletal age is a subjective and tedious examination process. Hence, automated assessment methods have been developed to replace manual evaluation in medical applications. In this study, a new fully automated method based on content-based image retrieval and using extreme learning machines (ELM) is designed and adapted to assess skeletal maturity. The main novelty of this approach is it overcomes the segmentation problem as suffered by existing systems. The estimation results of ELM models are compared with those of genetic programming (GP) and artificial neural networks (ANNs) models. The experimental results signify improvement in assessment accuracy over GP and ANN, while generalization capability is possible with the ELM approach. Moreover, the results are indicated that the ELM model developed can be used confidently in further work on formulating novel models of skeletal age assessment strategies. According to the experimental results, the new presented method has the capacity to learn many hundreds of times faster than traditional learning methods and it has sufficient overall performance in many aspects. It has conclusively been found that applying ELM is particularly promising as an alternative method for evaluating skeletal age. PMID:26402795

  13. Neighboring extremal guidance for systems with piecewise linear control using time as the reference variable

    NASA Astrophysics Data System (ADS)

    Libby, William A.

    1993-05-01

    A guidance law for the control of a system in the neighborhood of a nominal suboptimal trajectory is developed. The guidance law is demonstrated using a lunar launch problem with constraints at orbit entry. A set of precomputed gains is used by the guidance law to operate on an extremal path in the neighborhood of the suboptimal trajectory. The guidance law and gains are designed to minimize the change in the desired performance index while still satisfying the final path constraints. In the lunar launch problem, the nominal suboptimal trajectory minimizes the final time using piecewise linear control. This trajectory is obtained to provide a nominal control history. The guidance law is found by minimizing the second variation of the suboptimal trajectory performance index subject to the final constraints being satisfied. For the lunar launch problem, the guidance law leads to a set of gains that relates deviations from the suboptimal trajectory to required changes in the nominal control history. The deviations from the suboptimal trajectory, used together with the precomputed gains, determines the change in the nominal control history required to meet the final constraints while minimizing the change in the final time.

  14. Sources and transport systems for low energy extreme of ion implantation

    SciTech Connect

    Hershcovitch, A.; Batalin, V.A.; Bugaev, A.S.; Gushenets, V.I.; Alexeyenko, O.; Gurkova, E.; Johnson, B.M.; Kolomiets, A.A.; Kropachev, G.N.; Kuibeda, R.P.; Kulevoy, T.V.; Masunov, E.S.; Oks, E.M.; Pershin, V.I.; Polozov, S.M.; Poole, H.J.; Seleznev, D.N.; Storozhenko, P.A.; Vizir, A.; Svarovski, A.Ya.; Yakushin, P.; Yushkov, G.Yu.

    2010-06-06

    For the past seven years a joint research and development effort focusing on the design of steady state, intense ion sources has been in progress with the ultimate goal being to meet the two, energy extreme range needs of mega-electron-volt and 100's of electron-volt ion implanters. However, since the last Fortier is low energy ion implantation, focus of the endeavor has shifted to low energy ion implantation. For boron cluster source development, we started with molecular ions of decaborane (B{sub 10}H{sub 14}), octadecaborane (B{sub 18}H{sub 22}), and presently our focus is on carborane (C{sub 2}B{sub 10}H{sub 12}) ions developing methods for mitigating graphite deposition. Simultaneously, we are developing a pure boron ion source (without a working gas) that can form the basis for a novel, more efficient, plasma immersion source. Our Calutron-Berna ion source was converted into a universal source capable of switching between generating molecular phosphorous P{sub 4}{sup +}, high charge state ions, as well as other types of ions. Additionally, we have developed transport systems capable of transporting a very large variety of ion species, and simulations of a novel gasless/plasmaless ion beam deceleration method were also performed.

  15. Thermodynamic sensitivities in observed and simulated extreme-rain-producing mesoscale convective systems

    NASA Astrophysics Data System (ADS)

    Schumacher, R. S.; Peters, J. M.

    2015-12-01

    Mesoscale convective systems (MCSs) are responsible for a large fraction of warm-season extreme rainfall events over the continental United States, as well as other midlatitude regions globally. The rainfall production in these MCSs is determined by numerous factors, including the large-scale forcing for ascent, the organization of the convection, cloud microphysical processes, and the surrounding thermodynamic and kinematic environment. Furthermore, heavy-rain-producing MCSs are most common at night, which means that well-studied mechanisms for MCS maintenance and organization such as cold pools (gravity currents) are not always at work. In this study, we use numerical model simulations and recent field observations to investigate the sensitivity of low-level MCS structures, and their influences on rainfall, to the details of the thermodynamic environment. In particular, small alterations to the initial conditions in idealized and semi-idealized simulations result in comparatively large precipitation changes, both in terms of the intensity and the spatial distribution. The uncertainties in the thermodynamic enviroments in the model simulations will be compared with high-resolution observations from the Plains Elevated Convection At Night (PECAN) field experiment in 2015. The results have implications for the paradigms of "surface-based" versus "elevated" convection, as well as for the predictability of warm-season convective rainfall.

  16. Stress regulation of the PAN-proteasome system in the extreme halophilic archaeon Halobacterium.

    PubMed

    Chamieh, H; Marty, V; Guetta, D; Perollier, A; Franzetti, B

    2012-03-01

    In Archaea, the importance of the proteasome system for basic biological processes is only poorly understood. Proteasomes were partially purified from Halobacterium by native gradient density ultracentrifugation. The peptidase activity profiles showed that the 20S proteasome accumulation is altered depending on the physiological state of the cells. The amount of active 20S particles increases in Halobacterium cells as a response to thermal and low salt stresses. In the same conditions, Northern experiments showed a positive transcriptional regulation of the alpha and beta proteasome subunits as well as of the two proteasome regulatory ATPases, PANA and PANB. Co-immunoprecipitation experiments demonstrated the existence of a physical interaction between the two Proteasome Activating Nucleotidase (PAN) proteins in cell extracts. Thus, a direct regulation occurs on the PAN-proteasome components to adjust the protein degradation activity to growth and environmental constraints. These results also indicate that, in extreme halophiles, proteasome mediated proteolysis is an important aspect of low salt stress response. The tri-peptide vinyl sulfone inhibitor NLVS was used in cell cultures to study the in vivo function of proteasome in Halobacterium. The chemical inhibition of proteasomes was measured in the cellular extracts. It has no effect on cell growth and mortality under normal growth conditions as well as under heat shock conditions. These results suggest that the PAN activators or other proteases compensate for loss of proteasome activity in stress conditions.

  17. [Extreme types - a comparison of public health systems in Thuringia and the Warthegau].

    PubMed

    Vossen, J

    2013-11-01

    Special policing measures in Nazi Germany required centralisation in the public health service which was mainly achieved through the Law for the Unification of Municipal and State Health Administration in 1934. The long-term aim for public health officers was now hereditary and racial welfare. Several following legal regulations contributed to the implementation of a specific national-socialist health and social policy on the basis of racial hygiene and gave immense power to the health officers. Especially with the Law for the Prevention of Hereditarily Sick Offspring, compulsory sterilisation was legalised and resulted in about 400,000 victims up to 1945. The central force in this new system was the public health office. The most extreme variation of public health administration was launched in Thuringia, where professional powers and state authority implemented an extensive institutional machinery which managed to reinforce Nazi population policy almost to perfection. After the invasion of western Poland the Germans built up an inhumane regime in the annexed and occupied regions, persecuted and murdered the Polish population and tried to exterminate the Jewish people. Here the health officers of the Warthegau could promote a rigorously racial dominated population policy of segregation.

  18. Extreme Agility Micro Aerial Vehicle - Control of Hovering Maneuvers for a Mini-Aerial Vehicle with an Onboard Autopilot System

    DTIC Science & Technology

    2011-02-01

    Extreme Agility Micro Aerial Vehicle - Control of hovering maneuvers for a mini-aerial vehicle with an onboard autopilot system P.-R. Bilodeau AEREX...Micro Aerial Vehicle - Control of hovering maneuvers for a mini-aerial vehicle with an onboard autopilot system P.-R. Bilodeau AEREX Avionique inc...onboard autopilot. The implementation of the controllers on the onboard autopilot reduced system delays observed from an off board controller

  19. Impacts of Irrigation on Daily Extremes in the Coupled Climate System

    NASA Technical Reports Server (NTRS)

    Puma, Michael J.; Cook, Benjamin I.; Krakauer, Nir; Gentine, Pierre; Nazarenka, Larissa; Kelly, Maxwell; Wada, Yoshihide

    2014-01-01

    Widespread irrigation alters regional climate through changes to the energy and water budgets of the land surface. Within general circulation models, simulation studies have revealed significant changes in temperature, precipitation, and other climate variables. Here we investigate the feedbacks of irrigation with a focus on daily extremes at the global scale. We simulate global climate for the year 2000 with and without irrigation to understand irrigation-induced changes. Our simulations reveal shifts in key climate-extreme metrics. These findings indicate that land cover and land use change may be an important contributor to climate extremes both locally and in remote regions including the low-latitudes.

  20. Dynamics of the NGC 4636 globular cluster system. An extremely dark matter dominated galaxy?

    NASA Astrophysics Data System (ADS)

    Schuberth, Y.; Richtler, T.; Dirsch, B.; Hilker, M.; Larsen, S. S.; Kissler-Patig, M.; Mebold, U.

    2006-11-01

    Context: .We present the first dynamical study of the globular cluster system of NGC 4636. It is the southernmost giant elliptical galaxy of the Virgo cluster and is claimed to be extremely dark matter dominated, according to X-ray observations. Aims: .Globular clusters are used as dynamical tracers to investigate, by stellar dynamical means, the dark matter content of this galaxy. Methods: .Several hundred medium resolution spectra were acquired at the VLT with FORS 2/MXU. We obtained velocities for 174 globular clusters in the radial range 0.90 arcmin < R < 15.5 arcmin, or 0.5-9~Re in units of effective radius. Assuming a distance of 15 Mpc, the clusters are found at projected galactocentric distances in the range 4 to 70 kpc, the overwhelming majority within 30 kpc. The measured line-of-sight velocity dispersions are compared to Jeans-models. Results: .We find some indication of a rotation of the red (metal-rich) clusters about the minor axis. Out to a radius of 30 kpc, we find a roughly constant projected velocity dispersion for the blue clusters of σ ≈ 200~km s-1. The red clusters are found to have a distinctly different behavior: at a radius of about 3', the velocity dispersion drops by ~50~km s-1 to about 170~km s-1, which then remains constant out to a radius of 7'. The cause might be the steepening of the number density profile at ~3' observed for the red clusters. Using only the blue clusters as dynamical tracers, we perform Jeans-analyses for different assumptions of the orbital anisotropy. Enforcing the model dark halos to be of the NFW type, we determine their structural parameters. Depending on the anisotropy and the adopted M/L-values, we find that the dark matter fraction within one effective radius can vary between 20% and 50%, with most a probable range between 20% and 30%. The ambiguity of the velocity dispersion in the outermost bin is a main source of uncertainty. A comparison with cosmological N-body simulations reveals no striking

  1. Extreme Worlds of the Outer Solar System: Dynamic Processes on Uranus & Io

    NASA Astrophysics Data System (ADS)

    Kleer, Katherine Rebecca de

    A central goal of planetary science is the creation of a framework within which the properties of each solar system body can be understood as the product of initial conditions acted on by fundamental physical processes. The solar system's extreme worlds -- those objects that lie at the far ends of the spectrum in terms of planetary environment -- bring to light our misconceptions and present us with opportunities to expand and generalize this framework. Unraveling the processes at work in diverse planetary environments contextualizes our understanding of Earth, and provides a basis for interpreting specific signatures from planets beyond our own solar system. Uranus and Io, with their unusual planetary environments, present two examples of such worlds in the outer solar system. Uranus, one of the outer solar system's ice giants, produces an anomalously low heat flow and orbits the sun on its side. Its relative lack of bright storm features and its bizarre multi-decadal seasons provide insight into the relative effects of internal heat flow and time- varying solar insolation on atmospheric dynamics, while its narrow rings composed of dark, macroscopic particles encode the history of bombardment and satellite disruption within the system. Jupiter's moon Io hosts the most extreme volcanic activity anywhere in the solar system. Its tidally-powered geological activity provides a window into this satellite's interior, permitting rare and valuable investigations into the exchange of heat and materials between interiors and surfaces. In particular, Io provides a laboratory for studying the process of tidal heating, which shapes planets and satellites in our solar system and beyond. A comparison between Earth and Io contextualizes the volcanism at work on our home planet, revealing the effects of planetary size, atmospheric density, and plate tectonics on the style and mechanisms of geological activity. This dissertation investigates the processes at work on these solar

  2. Measurement of Thyroid Dose by TLD arising from Radiotherapy of Breast Cancer Patients from Supraclavicular Field

    PubMed Central

    Farhood, B.; Bahreyni Toossi, M.T.; Vosoughi, H.; Khademi, S.; Knaup, C.

    2016-01-01

    Background: Breast cancer is the most frequently diagnosed cancer and the leading global cause of cancer death among women worldwide. Radiotherapy plays a significant role in treatment of breast cancer and reduces locoregional recurrence and eventually improves survival. The treatment fields applied for breast cancer treatment include: tangential, axillary, supraclavicular and internal mammary fields. Objective: In the present study, due to the presence of sensitive organ such as thyroid inside the supraclavicular field, thyroid dose and its effective factors were investigated. Materials and Methods: Thyroid dose of 31 female patients of breast cancer with involved supraclavicular lymph nodes which had undergone radiotherapy were measured. For each patient, three TLD-100 chips were placed on their thyroid gland surface, and thyroid doses of patients were measured. The variables of the study include shield shape, the time of patient’s setup, the technologists’ experience and qualification. Finally, the results were analyzed by ANOVA test using SPSS 11.5 software. Results: The average age of the patients was 46±10 years. The average of thyroid dose of the patients was 140±45 mGy (ranged 288.2 and 80.8) in single fraction. There was a significant relationship between the thyroid dose and shield shape. There was also a significant relationship between the thyroid dose and the patient’s setup time. Conclusion: Beside organ at risk such as thyroid which is in the supraclavicular field, thyroid dose possibility should be reduced. For solving this problem, an appropriate shield shape, the appropriate time of the patient’s setup, etc. could be considered. PMID:27853722

  3. Using an Emergency Department Syndromic Surveillance System to investigate the impact of extreme cold weather events.

    PubMed

    Hughes, H E; Morbey, R; Hughes, T C; Locker, T E; Shannon, T; Carmichael, C; Murray, V; Ibbotson, S; Catchpole, M; McCloskey, B; Smith, G; Elliot, A J

    2014-07-01

    This report describes the development of novel syndromic cold weather public health surveillance indicators for use in monitoring the impact of extreme cold weather on attendances at EDs, using data from the 2010-11 and 2011-12 winters. A number of new surveillance indicators were created specifically for the identification and monitoring of cold weather related ED attendances, using the diagnosis codes provided for each attendance in the Emergency Department Syndromic Surveillance System (EDSSS), the first national syndromic surveillance system of its kind in the UK. Using daily weather data for the local area, a time series analysis to test the sensitivity of each indicator to cold weather was undertaken. Diagnosis codes relating to a health outcome with a potential direct link to cold weather were identified and assigned to a number of 'cold weather surveillance indicators'. The time series analyses indicated strong correlations between low temperatures and cold indicators in nearly every case. The strongest fit with temperature was cold related fractures in females, and that of snowfall was cold related fractures in both sexes. Though currently limited to a small number of sentinel EDs, the EDSSS has the ability to give near real-time detail on the magnitude of the impact of weather events. EDSSS cold weather surveillance fits well with the aims of the Cold Weather Plan for England, providing information on those particularly vulnerable to cold related health outcomes severe enough to require emergency care. This timely information aids those responding to and managing the effects on human health, both within the EDs themselves and in the community as a whole.

  4. Hadley Cell Variability and Extremes in Reanalysis Data: Links to Tropical and Subtropical Precipitating Systems

    NASA Astrophysics Data System (ADS)

    Stachnik, J. P.; Schumacher, C.

    2010-12-01

    The tropical Hadley circulation (HC, hereafter) accounts for the largest portion of global overturning in the meridional-vertical plane and is responsible for a significant redistribution of energy and heat throughout the global ocean-atmosphere system. The HC plays an important role in determining both local weather and climate (e.g., tropical rainfall patterns and suppression of precipitation in the subtropics) and can affect weather patterns at higher latitudes due to impacts on the general circulation. Reanalysis data is commonly used to study the behavior of the HC given the lack of observations over the tropical oceans, although previous studies have documented large discrepancies in the strength, location and latitudinal extent of the HC in older datasets. This study presents an HC climatology using multiple next generation and standard reanalysis datasets (including the ERA-Interim, ERA40, JRA25, NCEP/DOE and NCEP/NCAR). Variability in the long-term HC representation is quantified and explained by differences in the precipitation characteristics among datasets. Interannual variability and recent HC extremes are also explored with a new phenomenological approach, identifying changes in occurrence frequency and location of mesoscale precipitating systems as categorized by storm type (e.g., convective-stratiform, shallow-deep, etc.) using data collected by the Precipitation Radar (PR) onboard the TRMM satellite. Finally, satellite observations of storm type and other HC metrics derived from reanalysis are used to better elucidate HC latitudinal variability and determine those local areas of meridional overturning most important to comprising the zonal mean.

  5. Oscillation Responses to an Extreme Weather Event from a Deep Moored Observing System

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Dimarco, S. F.; Stoessel, M. M.; Zhang, X.; Ingle, S.

    2011-12-01

    In June 2007 tropical Cyclone Gonu passed directly over an ocean observing system consisting of four, deep autonomous mooring stations along the 3000 m isobath in the northern Arabian Sea. Gonu was the largest cyclone known to have occurred in the Arabian Sea or to strike the Arabian Peninsula. The mooring system was designed by Lighthouse R & D Enterprises, Inc. and installed in cooperation with the Oman Ministry of Agriculture and Fisheries Wealth. The instruments on the moorings continuously recorded water velocities, temperature, conductivity, pressure, dissolved oxygen and turbidity at multiple depths and at hourly intervals during the storm. Near-inertial oscillations at all moorings from thermocline to seafloor are coincident with the arrival of Gonu. Sub-inertial oscillations with periods of 2-10 days are recorded at the post-storm relaxation stage of Gonu, primarily in the thermocline. These oscillations consist of warm, saline water masses, likely originating from the Persian Gulf. Prominent 12.7-day sub-inertial waves, measured at a station ~300 km offshore, are bottom-intensified and have characteristics of baroclinic, topographically-trapped waves. Theoretical results from a topographically-trapped wave model are in a good agreement with the observed 12.7-day waves. The wavelength of the 12.7-day waves is about 590 km calculated from the dispersion relationship. Further analysis suggests that a resonant standing wave is responsible for trapping the 12.7-day wave energy inside the Sea of Oman basin. The observational results reported here are the first measurements of deepwater responses to a tropical cyclone in the Sea of Oman/Arabian Sea. Our study demonstrates the utility of sustained monitoring for studying the impact of extreme weather events on the ocean.

  6. Effective dose assessment in the maxillofacial region using thermoluminescent (TLD) and metal oxide semiconductor field-effect transistor (MOSFET) dosemeters: a comparative study

    PubMed Central

    Schulze, D; Wolff, J; Rottke, D

    2014-01-01

    Objectives: The objective of this study was to compare the performance of metal oxide semiconductor field-effect transistor (MOSFET) technology dosemeters with thermoluminescent dosemeters (TLDs) (TLD 100; Thermo Fisher Scientific, Waltham, MA) in the maxillofacial area. Methods: Organ and effective dose measurements were performed using 40 TLD and 20 MOSFET dosemeters that were alternately placed in 20 different locations in 1 anthropomorphic RANDO® head phantom (the Phantom Laboratory, Salem, NY). The phantom was exposed to four different CBCT default maxillofacial protocols using small (4 × 5 cm) to full face (20 × 17 cm) fields of view (FOVs). Results: The TLD effective doses ranged between 7.0 and 158.0 µSv and the MOSFET doses between 6.1 and 175.0 µSv. The MOSFET and TLD effective doses acquired using four different (FOV) protocols were as follows: face maxillofacial (FOV 20 × 17 cm) (MOSFET, 83.4 µSv; TLD, 87.6 µSv; −5%); teeth, upper jaw (FOV, 8.5 × 5.0 cm) (MOSFET, 6.1 µSv; TLD, 7.0 µSv; −14%); tooth, mandible and left molar (FOV, 4 × 5 cm) (MOSFET, 10.3 µSv; TLD, 12.3 µSv; −16%) and teeth, both jaws (FOV, 10 × 10 cm) (MOSFET, 175 µSv; TLD, 158 µSv; +11%). The largest variation in organ and effective dose was recorded in the small FOV protocols. Conclusions: Taking into account the uncertainties of both measurement methods and the results of the statistical analysis, the effective doses acquired using MOSFET dosemeters were found to be in good agreement with those obtained using TLD dosemeters. The MOSFET dosemeters constitute a feasible alternative for TLDs for the effective dose assessment of CBCT devices in the maxillofacial region. PMID:25143020

  7. Effective dose assessment in the maxillofacial region using thermoluminescent (TLD) and metal oxide semiconductor field-effect transistor (MOSFET) dosemeters: a comparative study.

    PubMed

    Koivisto, J; Schulze, D; Wolff, J; Rottke, D

    2014-01-01

    The objective of this study was to compare the performance of metal oxide semiconductor field-effect transistor (MOSFET) technology dosemeters with thermoluminescent dosemeters (TLDs) (TLD 100; Thermo Fisher Scientific, Waltham, MA) in the maxillofacial area. Organ and effective dose measurements were performed using 40 TLD and 20 MOSFET dosemeters that were alternately placed in 20 different locations in 1 anthropomorphic RANDO(®) head phantom (the Phantom Laboratory, Salem, NY). The phantom was exposed to four different CBCT default maxillofacial protocols using small (4 × 5 cm) to full face (20 × 17 cm) fields of view (FOVs). The TLD effective doses ranged between 7.0 and 158.0 µSv and the MOSFET doses between 6.1 and 175.0 µSv. The MOSFET and TLD effective doses acquired using four different (FOV) protocols were as follows: face maxillofacial (FOV 20 × 17 cm) (MOSFET, 83.4 µSv; TLD, 87.6 µSv; -5%); teeth, upper jaw (FOV, 8.5 × 5.0 cm) (MOSFET, 6.1 µSv; TLD, 7.0 µSv; -14%); tooth, mandible and left molar (FOV, 4 × 5 cm) (MOSFET, 10.3 µSv; TLD, 12.3 µSv; -16%) and teeth, both jaws (FOV, 10 × 10 cm) (MOSFET, 175 µSv; TLD, 158 µSv; +11%). The largest variation in organ and effective dose was recorded in the small FOV protocols. Taking into account the uncertainties of both measurement methods and the results of the statistical analysis, the effective doses acquired using MOSFET dosemeters were found to be in good agreement with those obtained using TLD dosemeters. The MOSFET dosemeters constitute a feasible alternative for TLDs for the effective dose assessment of CBCT devices in the maxillofacial region.

  8. Global Fluctuations in Physical Systems:. a Subtle Interplay Between Sum and Extreme Value Statistics

    NASA Astrophysics Data System (ADS)

    Clusel, Maxime; Bertin, Eric

    Fluctuations of global additive quantities, like total energy or magnetization for instance, can in principle be described by statistics of sums of (possibly correlated) random variables. Yet, it turns out that extreme values (the largest value among a set of random variables) may also play a role in the statistics of global quantities, in a direct or indirect way. This review discusses different connections that may appear between problems of sums and of extreme values of random variables, and emphasizes physical situations in which such connections are relevant. Along this line of thought, standard convergence theorems for sums and extreme values of independent and identically distributed random variables are recalled, and some rigorous results as well as more heuristic reasonings are presented for correlated or non-identically distributed random variables. More specifically, the role of extreme values within sums of broadly distributed variables is addressed, and a general mapping between extreme values and sums is presented, allowing us to identify a class of correlated random variables whose sum follows (generalized) extreme value distributions. Possible applications of this specific class of random variables are illustrated on the example of two simple physical models. A few extensions to other related classes of random variables sharing similar qualitative properties are also briefly discussed, in connection with the so-called BHP distribution.

  9. Changes in the South American Monsoon System and Impacts on Extreme Precipitation

    NASA Astrophysics Data System (ADS)

    Carvalho, L. V.; Silva Dias, M. A.; Silva Dias, P. L.; Jones, C.; Liebmann, B.; da Silva, A. E.

    2011-12-01

    The South American Monsoon System (SAMS) is the most important climatic feature in South America and affects millions of people. SAMS is characterized by pronounced seasonality in rainfall, circulation and moisture transport. The South Atlantic convergence zone (SACZ) is a component of SAMS and plays significant role for the variability of precipitation in highly populated areas of South America. Using NCEP/NCAR reanalysis (1948-2010) and several distinct precipitation datasets we show evidence that the duration and amplitude of SAMS and the amplitude of the SACZ have increased in the last 62 years. The metrics used to investigate interannual to decadal variations of SAMS and the SACZ are based on a large-scale index obtained from combined Empirical Orthogonal Functions (CEOF) of circulation, temperature and specific humidity. The extensive warming of tropical South America and adjacent oceans has played a significant role for changes in SAMS characteristics. Due to the equatorward large geographical extent of South America, the warming of recent decades has been more pronounced in the lower troposphere of tropical regions compared with the subtropics. Nevertheless, the warming is not uniform and large rates of increase in temperature are observed over eastern Brazil. These changes have affected land-ocean temperature gradients and the intensity of the trade winds. As a consequence, the easterly vertically integrated moisture transport over eastern Amazon has weakened and moisture convergence has been replaced by moisture divergence in recent decades. On the other hand, the northerly moisture transport and moisture convergence have intensified over central and southeastern Brazil, resulting in the strengthening of SAMS. The interplay of local and remote forcings are likely responsible for the intensification of the SACZ. We use several precipitation datasets with different spatial resolution and show that these changes have significantly affected patters of extreme

  10. Evaluate the radioactivity along the central thimble hole of a decommissioned heavy water research reactor using TLD approach.

    PubMed

    Lee, Lun-Hui; Sher, Hai-Feng; Lu, I-Hsin; Pan, Lung-Kwang

    2012-04-01

    The radioactivity along the central thimble hole of a decommissioned heavy water research reactor, TRR, was evaluated using TLD approach. The decay radionuclide was verified to be Co-60. The dose along the TRR central thimble hole was detected and revised by performing an unfolding analysis. The revised data reduced to 70-90% of the original data (for example, the maximum dose rate was reduced from 6447 to 4831 mSv/h,) and were more reliable. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Determination of Radiation Energy Response for Thermoluminescent Dosimeter TLD-100: Determination of Organ Dose in Diagnostic Radiology

    SciTech Connect

    Deda, Antoneta; Telhaj, Ervis

    2009-04-19

    TLD-100 (thermoluminescent dosimeter) cards (chips) were calibrated using X-rays with energies of 25-250 kV produced by a Cs-137 source. The energy responses of lithium fluoride crystals for different energies of X-rays were studied. QA/QC was then performed in the Albanian Ionizing Radiation Metrology Laboratory. Based on the QA/QC results, the chips were used to study the doses to different organs in diagnostic radiology. Organ dose was evaluated after calculation of e dose in air (Kair), using an ionizing chamber.

  12. Prospects for MOEMS-based adaptive optical systems on extremely large telescopes

    NASA Astrophysics Data System (ADS)

    Zamkotsian, Frédéric; Dohlen, Kjetil

    Different research groups around the world are currently involved in the design of extremely large optical telescopes, ranging from 40 to 100m. These telescopes will rely on the availability of highly performing adaptive optical systems with of the order of 100 000 actuators. This number of actuators is prohibitive for conventional technology (stacked piezoelectric actuators, bimorph mirrors), but can be achieved by the development of new technologies based on micro-opto-electro-mechanical systems (MOEMS). MOEMS devices are realized by the mature microelectronics process and they show great potential to reach the specifications required by AO in astronomy. Within the AO-ELT RTN, the Laboratoire d'Astrophysique de Marseille is designing and developing new MDM in collaboration with the LAAS, a leading French micro-opto-electronics research laboratory. After realization of prototypes, tests will be performed on specific characterization bench set-ups in our laboratory. We review the three main kinds of micro-deformable mirrors (MDM) which are under study and illustrate their great potential. Driven by electrostatic fields, the concepts differ in terms of surface quality, size of the device, number of actuators, inter-actuator coupling effects, deformation motion (maximal deflection) and driving voltage. A major advantage of the MOEMS technology is the possibility to build complete addressing and driving electronics into the device. However, MOEMS present some technological limitations regarding actuators stroke (< 10 μ m) and overall size (size of the wafer). These limitations stress some parameters of the AO system optical design, such as the possibility to correct low order perturbations, the axial separation between the deformable mirrors (DM), and the size of the internal pupil. To counter the limited stroke problem, we propose a multistage AO concept. Tip-tilt and low-order corrections can be achieved with conventional technology, leaving only high order

  13. Extreme value laws for fractal intensity functions in dynamical systems: Minkowski analysis

    NASA Astrophysics Data System (ADS)

    Mantica, Giorgio; Perotti, Luca

    2016-09-01

    Typically, in the dynamical theory of extremal events, the function that gauges the intensity of a phenomenon is assumed to be convex and maximal, or singular, at a single, or at most a finite collection of points in phase-space. In this paper we generalize this situation to fractal landscapes, i.e. intensity functions characterized by an uncountable set of singularities, located on a Cantor set. This reveals the dynamical rôle of classical quantities like the Minkowski dimension and content, whose definition we extend to account for singular continuous invariant measures. We also introduce the concept of extremely rare event, quantified by non-standard Minkowski constants and we study its consequences to extreme value statistics. Limit laws are derived from formal calculations and are verified by numerical experiments. Dedicated to the memory of Joseph Ford, on the twentieth anniversary of his departure.

  14. Estimation of fatigue and extreme load distributions from limited data with application to wind energy systems.

    SciTech Connect

    Fitzwater, LeRoy M.

    2004-01-01

    An estimate of the distribution of fatigue ranges or extreme loads for wind turbines may be obtained by separating the problem into two uncoupled parts, (1) a turbine specific portion, independent of the site and (2) a site-specific description of environmental variables. We consider contextually appropriate probability models to describe the turbine specific response for extreme loads or fatigue. The site-specific portion is described by a joint probability distribution of a vector of environmental variables, which characterize the wind process at the hub-height of the wind turbine. Several approaches are considered for combining the two portions to obtain an estimate of the extreme load, e.g., 50-year loads or fatigue damage. We assess the efficacy of these models to obtain accurate estimates, including various levels of epistemic uncertainty, of the turbine response.

  15. Extreme responses of non-linear dynamic systems using constrained simulations

    SciTech Connect

    Harland, L.A.; Vugts, J.H.; Jonathan, P.; Taylor, P.H.

    1996-12-31

    The dynamic behavior of structures in the offshore environment is complex, especially in extreme storm conditions. The most accurate methods for estimating structural behavior are based on extensive random time domain simulations of the ocean surface to obtain statistics of the extreme response in (typically) a 3 hour period of a severe storm. However, random time domain simulation is time-consuming and expensive for both the computer and the engineer. In this work the authors use a method to determine the distribution of the extreme structural response in a robust, faster and cheaper way than with full random simulations. This method, which is based on constrained random simulations, has been successfully developed using a grossly simplified model of a jack-up. The aim of this study is now to include more realistic modelling parameters in order to demonstrate that the method can be successfully applied to real problems and that accurate results can be obtained with relatively little effort.

  16. Dose and scatter characteristics of a novel cone beam CT system for musculoskeletal extremities

    NASA Astrophysics Data System (ADS)

    Zbijewski, W.; Sisniega, A.; Vaquero, J. J.; Muhit, A.; Packard, N.; Senn, R.; Yang, D.; Yorkston, J.; Carrino, J. A.; Siewerdsen, J. H.

    2012-03-01

    A novel cone-beam CT (CBCT) system has been developed with promising capabilities for musculoskeletal imaging (e.g., weight-bearing extremities and combined radiographic / volumetric imaging). The prototype system demonstrates diagnostic-quality imaging performance, while the compact geometry and short scan orbit raise new considerations for scatter management and dose characterization that challenge conventional methods. The compact geometry leads to elevated, heterogeneous x-ray scatter distributions - even for small anatomical sites (e.g., knee or wrist), and the short scan orbit results in a non-uniform dose distribution. These complex dose and scatter distributions were investigated via experimental measurements and GPU-accelerated Monte Carlo (MC) simulation. The combination provided a powerful basis for characterizing dose distributions in patient-specific anatomy, investigating the benefits of an antiscatter grid, and examining distinct contributions of coherent and incoherent scatter in artifact correction. Measurements with a 16 cm CTDI phantom show that the dose from the short-scan orbit (0.09 mGy/mAs at isocenter) varies from 0.16 to 0.05 mGy/mAs at various locations on the periphery (all obtained at 80 kVp). MC estimation agreed with dose measurements within 10-15%. Dose distribution in patient-specific anatomy was computed with MC, confirming such heterogeneity and highlighting the elevated energy deposition in bone (factor of ~5-10) compared to soft-tissue. Scatter-to-primary ratio (SPR) up to ~1.5-2 was evident in some regions of the knee. A 10:1 antiscatter grid was found earlier to result in significant improvement in soft-tissue imaging performance without increase in dose. The results of MC simulations elucidated the mechanism behind scatter reduction in the presence of a grid. A ~3-fold reduction in average SPR was found in the MC simulations; however, a linear grid was found to impart additional heterogeneity in the scatter distribution

  17. Between L2 and SLI: inflections and prepositions in the Hebrew of bilingual children with TLD and monolingual children with SLI.

    PubMed

    Armon-Lotem, Sharon

    2014-01-01

    Verb inflectional morphology and prepositions are loci of difficulty for bilingual children with typical language development (TLD) as well as children with Specific Language Impairment (SLI). This paper examines errors in these linguistic domains in these two populations. Bilingual English-Hebrew and Russian-Hebrew preschool children, aged five to seven, with TLD, and age-matched monolingual Hebrew-speaking children with SLI, were tested using sentence completion and sentence imitation tasks in their L2 Hebrew. Our findings show that, despite the similarity in the locus of errors, the two populations can be distinguished by both the quantity and the quality of errors. While bilingual children with TLD had substitution errors often motivated by the first language, most of the errors of monolingual children with SLI involved omission of the whole morpheme or feature reduction. This difference in the nature of the errors is discussed in terms of bilingual processing vs. impaired representation.

  18. Study of real heating profiles in routine TLD readout: influences of temperature lags and non-linearities in the heating profiles on the glow curve shape.

    PubMed

    Stadtmann, H; Delgado, A; Gómez-Ros, J M

    2002-01-01

    This paper reports on the results of a heating profile analysis using a commercial routine read-out system with non-contact hot nitrogen heating, using linear heating gas profiles. Glow curves of TLD-100 were analysed for different linear heating gas rates from 1 degree C x s(-1) to 30 degrees C x s(-1). The analysis of the individual peak maxima (Peak 2-5) leads to an approximation of the real heating profile in the TL detector. It was found that the real heating profile deviates strongly from linearity, and that the temperature lag between the heating gas and the detector reaches values up to some tens of degrees C. The consequences of this non-linearity, with respect to the resulting glow curves, are discussed in this paper. These results lead to a better understanding of the shape of routine TL glow curves and help to improve the use of glow curves analysis in routine services. In addition, a simple procedure is described which allows calculation of the real heating profile based on the heating gas temperature profile. This model shows a very good match between experimental data and calculated values.

  19. Radiation damage and sensitization effects on thermoluminescence of LiF:Mg,Ti (TLD-700)

    NASA Astrophysics Data System (ADS)

    Farag, M. A.; Sadek, A. M.; Shousha, Hany. A.; El-Hagg, A. A.; Atta, M. R.; Kitis, G.

    2017-09-01

    The radiation damage effects and enhancement the thermoluminescence (TL) efficiency of LiF:Mg,Ti (TLD-700)dosimeters via sensitization method were discussed. Attempts to eliminate the effects of damage and sensitization were made using different types of annealing processes. The results showed that after irradiating the dosimeters with dose > 250 Gy of 60Co gamma source, damage effects were observed. The sensitivity of the total area under the curve was decreased by a factor of ∼0.5 after irradiation at a pre-test dose of 2 kGy. However, the effects of radiation damage on each glow-peak are different. The glow-peak 2 was the only peak that was not affected by the high-dose irradiation. It has been shown that the degree of the radiation damage effect is related to the maximum dose-response function, f(D)max of the glow-peak. In general, significant radiation damage effects were observed for the glow-peaks of high f(D)max . Post-irradiation anneal at 280 °C for 30 min causes dramatic effects on the shape of the glow-curve and as well as on the sensitivity of the dosimeters. An increasing by a factor of ∼35 in the sensitivity of the total area under the curve was observed at a pre-test dose of 2 kGy. Improving the sensitivity of peak 7 by a factor of∼22 was the dominant factor in increasing the sensitivity of the dosimeters. On the other hand, an increasing by factors of ∼2.5 and ∼4 was found for peaks 2 and 5 respectively. On the other hand, a decreasing by a factor ∼0.5 was observed for peaks 3 and 4. At pre-test dose levels >250 Gy, a very strange and high intensity tail was observed in the high-temperature region of the glow-curves. The readout anneal was not enough to remove this tail. While, the furnace anneal could eliminate the sensitization effects but not the radiation damage effects on the sensitivity of the dosimeters.

  20. Arterial reconstruction after mangled extremity: injury severity scoring systems are not predictive of limb salvage.

    PubMed

    Elsharawy, Mohamed Amin

    2005-01-01

    The Vascular Unit at Suez Canal University Hospital in Egypt covers a wide area with high rates of severe injuries. This is a prospective study of mangled extremities to identify risk factors associated with limb loss in these patients. Between December 2000 and August 2003, a prospective study on all patients with arterial injuries in mangled extremities was undertaken. All patients were scored using the Mangled Extremity Severity Score (MESS) and the Mangled Extremity Severity Index (MESI). During this period, arterial reconstruction was performed in 62 patients. Primary patency, secondary patency, and limb salvage rates were 81%, 85.5%, and 93.5%, respectively. The only factor affecting limb salvage (statistical trend) was the site of trauma (upper limb 100% vs lower limb 89%; p = .08%). There was no significant effect related to the mechanism of trauma (blunt 90% vs stab 100%; p = .125), MESS (< 7, 100% vs > 7, 91%; p = .22), and MESI (< 20, 100% vs > 20, 90.5%; p = .154). Upper limb injuries were the least likely to lead to amputation. We recommend that all injuries, whatever their score, should be surgically explored before treatment decisions are made.

  1. Image-guided method for TLD-based in vivo rectal dose verification with endorectal balloon in proton therapy for prostate cancer

    SciTech Connect

    Hsi, Wen C.; Fagundes, Marcio; Zeidan, Omar; Hug, Eugen; Schreuder, Niek

    2013-05-15

    Purpose: To present a practical image-guided method to position an endorectal balloon that improves in vivo thermoluminiscent dosimeter (TLD) measurements of rectal doses in proton therapy for prostate cancer. Methods: TLDs were combined with endorectal balloons to measure dose at the anterior rectal wall during daily proton treatment delivery. Radiopaque metallic markers were employed as surrogates for balloon position reproducibility in rotation and translation. The markers were utilized to guide the balloon orientation during daily treatment employing orthogonal x-ray image-guided patient positioning. TLDs were placed at the 12 o'clock position on the anterior balloon surface at the midprostatic plane. Markers were placed at the 3 and 9 o'clock positions on the balloon to align it with respect to the planned orientation. The balloon rotation along its stem axis, referred to as roll, causes TLD displacement along the anterior-posterior direction. The magnitude of TLD displacement is revealed by the separation distance between markers at opposite sides of the balloon on sagittal x-ray images. Results: A total of 81 in vivo TLD measurements were performed on six patients. Eighty-three percent of all measurements (65 TLD readings) were within +5% and -10% of the planning dose with a mean of -2.1% and a standard deviation of 3.5%. Examination of marker positions with in-room x-ray images of measured doses between -10% and -20% of the planned dose revealed a strong correlation between balloon roll and TLD displacement posteriorly from the planned position. The magnitude of the roll was confirmed by separations of 10-20 mm between the markers which could be corrected by manually adjusting the balloon position and verified by a repeat x-ray image prior to proton delivery. This approach could properly correct the balloon roll, resulting in TLD positioning within 2 mm along the anterior-posterior direction. Conclusions: Our results show that image-guided TLD-based in vivo

  2. Injectable Ceramic Microcast Silicon Carbonitride (SiCN) Microelectromechanical System (MEMS) for Extreme Temperature Environments with Extension: Micro Packages for Nano-Devices

    DTIC Science & Technology

    2004-01-01

    MICROELECTROMECHANICAL SYSTEM (MEMS) FOR EXTREME TEMPERATURE ENVIRONMENTS WITH EXTENSION: MICRO -PACKAGES FOR NANO -DEVICES University of Colorado at Boulder...MICROELECTROMECHANICAL SYSTEM (MEMS) FOR EXTREME TEMPERATURE ENVIRONMENTS WITH EXTENSION: MICRO -PACKAGES FOR NANO -DEVICES 6. AUTHOR(S) Victor M...investigate a new micro -packaging technology to create a high-vacuum, sealed environment for nano -devices integrated with other electronic or RF

  3. A hybrid fuzzy logic and extreme learning machine for improving efficiency of circulating water systems in power generation plant

    NASA Astrophysics Data System (ADS)

    Aziz, Nur Liyana Afiqah Abdul; Siah Yap, Keem; Afif Bunyamin, Muhammad

    2013-06-01

    This paper presents a new approach of the fault detection for improving efficiency of circulating water system (CWS) in a power generation plant using a hybrid Fuzzy Logic System (FLS) and Extreme Learning Machine (ELM) neural network. The FLS is a mathematical tool for calculating the uncertainties where precision and significance are applied in the real world. It is based on natural language which has the ability of "computing the word". The ELM is an extremely fast learning algorithm for neural network that can completed the training cycle in a very short time. By combining the FLS and ELM, new hybrid model, i.e., FLS-ELM is developed. The applicability of this proposed hybrid model is validated in fault detection in CWS which may help to improve overall efficiency of power generation plant, hence, consuming less natural recourses and producing less pollutions.

  4. Extreme Environments of Next-Generation Energy Systems and Materials: Can They Peacefully Co-Exist? (452nd Brookhaven Lecture)

    SciTech Connect

    Simos, Nikolaos

    2009-06-17

    "What happens to conventional metals near the ocean?" you might ask the workers who are repairing the water tower at Jones Beach. They will tell you that both the tower's steel framework and copper roof show extensive corrosion from the salty air. To power future generations of cars, homes, utility plants, and even particle accelerators, unprecedented levels of efficiency will be needed. Such efficiency will require new unconventional alloys and composite materials that can also withstand high temperatures, intense radiation fluxes, high stresses, and other extreme conditions in highly corrosive environments that accelerate the aging and weakening of materials, as salty air weakens steel and copper. During the lecture, Simos will discuss the demands of next-generation energy systems and focus on the extreme conditions that materials used in these systems will perform under. He will also explain Brookhaven Lab's role in past, ongoing, and future experiments aimed to analyze and address materials' abilities to endure these conditions.

  5. Extremely low frequency (ELF) communication system--ecological monitoring program: Wisconsin bird studies. Final report, June 1984-September 1990

    SciTech Connect

    Hanowski, J.M.; Blake, J.G.; Niemi, G.J.; Collins, P.T.

    1991-02-01

    This study was designed to isolate effects of electromagnetic (EM) fields produced by extremely low frequency (ELF) antenna systems on bird species breeding in or migrating through Wisconsin. Specifically, the aim was to determine any differences in bird species richness and abundance between areas close to the antenna and those far enough away to be unaffected by the antenna. Characteristics examined included total species richness and abundance, abundance of common bird species, and abundance of birds within selected guilds. Measurements of vegetation identified differences and similarities between control and treatment areas. Habitat variables were used in analysis of covariance (ANCOVA) to compare numbers of abundant bird species in control versus treatment areas after adjustments for habitat differences. Extremely low frequency, Ecology, Electromagnetic fields, ELF Communications system, Environmental studies, ELF Ecological monitoring program.

  6. Deficits in Approximate Number System Acuity and Mathematical Abilities in 6.5-Year-Old Children Born Extremely Preterm

    PubMed Central

    Libertus, Melissa E.; Forsman, Lea; Adén, Ulrika; Hellgren, Kerstin

    2017-01-01

    Preterm children are at increased risk for poor academic achievement, especially in math. In the present study, we examined whether preterm children differ from term-born children in their intuitive sense of number that relies on an unlearned, approximate number system (ANS) and whether there is a link between preterm children’s ANS acuity and their math abilities. To this end, 6.5-year-old extremely preterm (i.e., <27 weeks gestation, n = 82) and term-born children (n = 89) completed a non-symbolic number comparison (ANS acuity) task and a standardized math test. We found that extremely preterm children had significantly lower ANS acuity than term-born children and that these differences could not be fully explained by differences in verbal IQ, perceptual reasoning skills, working memory, or attention. Differences in ANS acuity persisted even when demands on visuo-spatial skills and attention were reduced in the ANS task. Finally, we found that ANS acuity and math ability are linked in extremely preterm children, similar to previous results from term-born children. These results suggest that deficits in the ANS may be at least partly responsible for the deficits in math abilities often observed in extremely preterm children. PMID:28744252

  7. Deficits in Approximate Number System Acuity and Mathematical Abilities in 6.5-Year-Old Children Born Extremely Preterm.

    PubMed

    Libertus, Melissa E; Forsman, Lea; Adén, Ulrika; Hellgren, Kerstin

    2017-01-01

    Preterm children are at increased risk for poor academic achievement, especially in math. In the present study, we examined whether preterm children differ from term-born children in their intuitive sense of number that relies on an unlearned, approximate number system (ANS) and whether there is a link between preterm children's ANS acuity and their math abilities. To this end, 6.5-year-old extremely preterm (i.e., <27 weeks gestation, n = 82) and term-born children (n = 89) completed a non-symbolic number comparison (ANS acuity) task and a standardized math test. We found that extremely preterm children had significantly lower ANS acuity than term-born children and that these differences could not be fully explained by differences in verbal IQ, perceptual reasoning skills, working memory, or attention. Differences in ANS acuity persisted even when demands on visuo-spatial skills and attention were reduced in the ANS task. Finally, we found that ANS acuity and math ability are linked in extremely preterm children, similar to previous results from term-born children. These results suggest that deficits in the ANS may be at least partly responsible for the deficits in math abilities often observed in extremely preterm children.

  8. Compilation of 1986 annual reports of the Navy ELF (Extremely Low Frequency) communications system ecological monitoring program, volume 2

    NASA Astrophysics Data System (ADS)

    1987-07-01

    The U.S. Navy is conducting a long-term program to monitor for possible effects from the operation of its Extremely Low Frequency (ELF) Communications System to resident biota and their ecological relationships. This report documents progress of the following studies: soil amoeba; soil and litter arthropoda and earthworm studies; biological studies on pollinating insects: megachilid bees; and small vertebrates: small mammals and nesting birds.

  9. Which weather systems are projected to cause future changes in mean and extreme precipitation in CMIP5 simulations?

    NASA Astrophysics Data System (ADS)

    Utsumi, Nobuyuki; Kim, Hyungjun; Kanae, Shinjiro; Oki, Taikan

    2016-09-01

    Future changes in precipitation due to climate change are of great concern to society. However, questions such as "Which weather systems will cause which changes?" and "Is the relative importance of these weather systems likely to change in the future?" have not been addressed fully yet. Here we present the first global estimates of the relative contributions of different weather systems (i.e., tropical cyclones, extratropical cyclones including fronts, and others) to changes in annual mean and extreme precipitation in the late 21st century using multimodel projections of the Coupled Model Intercomparison Project Phase 5. Although the models present biases in tropical cyclones over southern hemisphere, in particular, the representations of global weather system patterns are comparable to the reanalysis data. Total precipitation from tropical cyclones decreases (increases) in the tropics (subtropics) and that from extratropical cyclones including fronts decreases (increases) on the equatorial (poleward) side of the storm tracks. In addition, the mean intensity and frequency of system-wise precipitation can change significantly even without considerable changes in annual amounts. We found that the subtropics, particularly in the Pacific and North Atlantic, are the regions where the proportions of precipitation by weather systems in annual mean and extreme precipitation display notable changes, suggesting distinct shifts in climate regimes. These regions have a common feature: they undergo the influence of several distinct weather systems in the present climate. In regions where climate regime shifts are projected, even the weather systems that have a minor contribution to precipitation in the present climate may cause considerable changes in annual and extreme precipitation.

  10. Butterflies, Black swans and Dragon kings: How to use the Dynamical Systems Theory to build a "zoology" of mid-latitude circulation atmospheric extremes?

    NASA Astrophysics Data System (ADS)

    Faranda, D.; Yiou, P.; Alvarez-Castro, M. C. M.

    2015-12-01

    A combination of dynamical systems and statistical techniques allows for a robust assessment of the dynamical properties of the mid-latitude atmospheric circulation. Extremes at different spatial and time scales are not only associated to exceptionally intense weather structures (e.g. extra-tropical cyclones) but also to rapid changes of circulation regimes (thunderstorms, supercells) or the extreme persistence of weather structure (heat waves, cold spells). We will show how the dynamical systems theory of recurrence combined to the extreme value theory can take into account the spatial and temporal dependence structure of the mid-latitude circulation structures and provide information on the statistics of extreme events.

  11. System Characterization of MAHI EXO-II: A Robotic Exoskeleton for Upper Extremity Rehabilitation.

    PubMed

    French, James A; Rose, Chad G; O'Malley, Marcia K

    2014-10-01

    This paper presents the performance characterization of the MAHI Exo-II, an upper extremity exoskeleton for stroke and spinal cord injury (SCI) rehabilitation, as a means to validate its clinical implementation and to provide depth to the literature on the performance characteristics of upper extremity exoskeletons. Individuals with disabilities arising from stroke and SCI need rehabilitation of the elbow, forearm, and wrist to restore the ability to independently perform activities of daily living (ADL). Robotic rehabilitation has been proposed to address the need for high intensity, long duration therapy and has shown promising results for upper limb proximal joints. However, upper limb distal joints have historically not benefitted from the same focus. The MAHI Exo-II, designed to address this shortcoming, has undergone a static and dynamic performance characterization, which shows that it exhibits the requisite qualities for a rehabilitation robot and is comparable to other state-of-the-art designs.

  12. System Characterization of MAHI EXO-II: A Robotic Exoskeleton for Upper Extremity Rehabilitation

    PubMed Central

    French, James A.; Rose, Chad G.; O'Malley, Marcia K.

    2015-01-01

    This paper presents the performance characterization of the MAHI Exo-II, an upper extremity exoskeleton for stroke and spinal cord injury (SCI) rehabilitation, as a means to validate its clinical implementation and to provide depth to the literature on the performance characteristics of upper extremity exoskeletons. Individuals with disabilities arising from stroke and SCI need rehabilitation of the elbow, forearm, and wrist to restore the ability to independently perform activities of daily living (ADL). Robotic rehabilitation has been proposed to address the need for high intensity, long duration therapy and has shown promising results for upper limb proximal joints. However, upper limb distal joints have historically not benefitted from the same focus. The MAHI Exo-II, designed to address this shortcoming, has undergone a static and dynamic performance characterization, which shows that it exhibits the requisite qualities for a rehabilitation robot and is comparable to other state-of-the-art designs. PMID:25984380

  13. Dominant processes of extreme rainfall-producing mesoscale convective system over southeastern Korea: 7 July 2009 case

    NASA Astrophysics Data System (ADS)

    Jeong, J.-H.; Lee, D.-I.; Wang, C.-C.; Han, I.-S.

    2015-10-01

    An extreme rainfall-producing mesoscale convective system (MCS) associated with the Changma front in southeastern Korea was investigated using observational data. This event recorded historic rainfall and led to devastating flash floods and landslides in the Busan metropolitan area on 7 July 2009. The aim of the present study is to analyze and better understand the synoptic and mesoscale environment, and the behavior of quasi-stationary MCS causing extreme rainfall. Synoptic and mesoscale analyses indicate that the MCS and heavy rainfall occurred association with a stationary front which resembled a warm front in structure. A strong southwesterly low-level jet (LLJ) transported warm and humid air and supplied the moisture toward the front, and the air rose upwards above the frontal surface. As the moist air was conditionally unstable, repeated upstream initiation of deep convection by back-building occurred at the coastline, while old cells moved downstream parallel to the convective line with training effect. Because the motion of convective cells nearly opposed the backward propagation, the system as a whole moved slowly. The back-building behavior was linked to the convectively produced cold pool and its outflow boundary, which played an essential role in the propagation and maintenance of the rainfall system. As a result, the quasi-stationary MCS caused a prolonged duration of heavy rainfall, leading to extreme rainfall over the Busan metropolitan area.

  14. Extreme ultraviolet marking system for anti-counterfeiting tags with adjustable security level

    NASA Astrophysics Data System (ADS)

    Di Lazzaro, P.; Bollanti, S.; Flora, F.; Mezi, L.; Murra, D.; Torre, A.; Bonfigli, F.; Montereali, R. M.; Vincenti, M. A.

    2012-01-01

    We present a recently patented apparatus which consists of an extreme ultraviolet radiation source writing invisible patterns on thin tags of alkali halides. The tags patterned using this method are almost impossible to counterfeit, and offer a much better protection against fakes than available anti-counterfeiting techniques. We will discuss if this novel technology is ready for industrial production of anti-counterfeiting tags.

  15. ELF (Extremely Low Frequency) Communications System Ecological Monitoring Program: Slime Mold Studies

    DTIC Science & Technology

    1990-01-01

    the slime mold Physarum polycephalum to extremely low frequency (ELF) electromagnetic fields (EMF) simulating those generated by the Navy’s ELF...stronger (0.7 V/m, 0.2mT) than the proposed maximum fields generated by the antenna. The slime mold Physarum polycephalum was selected as the experimental...fields. VI. CONCLUSIONS: 1. The slime mold Physarum polycephalum was grown on agar for about 140 days during which time it was exposed to both the

  16. Geochemistry meets Biochemistry: Minimal Metabolic Systems in Extremely Thermophilic Bacteria from Geothermal Environments.

    NASA Astrophysics Data System (ADS)

    Robb, F. T.; DiRuggiero, J.; Davila, J.; Schwartz, M.

    2002-05-01

    A growing body of research confirms that extreme thermophiles can grow at temperatures of at least 113.5oC, at elevated pressures. Other archaeal isolates can thrive in hostile chemical conditions, for example pH 0.8. We, and others have shown that hyperthermophiles have novel heat shock proteins and other chaperonins that permit them to maintain native protein structures in unfavorable conditions. They are also able to survive using individual gases and gas mixtures We have determined the complete genome sequence of a bacterial isolate from thermal mats on the Kamchatka Peninsula that grows on a salts medium with carbon monoxide as its sole energy and carbon source. It forms hydrogen in proportion with CO consumption. The minimal size of its genome, 2.1 megabase pairs, and its ability to form spores have led us to propose that this autotrophic bacterium can serve as a model for ancestral microbial cells. We have isolated a new class of thermophilic, extremely radiation resistant bacteria from Yellowstone National Park that can withstand space vacuum for extended periods. In collaboration with NASA Goddard, we have exposed filters coated with one of these isolates to space vacuum and to extreme UV during a sounding rocket flight at White Sands. Deinococcus radiodurans, the most desiccation and radiation resistant organism characterized so far, was exposed as a control. The new isolate was slightly more desiccation resistant than D. radiodurans, and significantly more resistant than D. radiodurans to extreme UV at 34 nm. These studies may provide insights into the potential for viable bacterial cells to survive transmission through space, a phenomenon usually referred to as panspermia.

  17. Lower Extremity Ulcers in Systemic Sclerosis: Features and Response to Therapy

    PubMed Central

    Shanmugam, Victoria K.; Price, Patricia; Attinger, Christopher E.; Steen, Virginia D.

    2010-01-01

    Nondigital lower extremity ulcers are a difficult to treat complication of scleroderma, and a significant cause of morbidity. The purpose of this study was to evaluate the prevalence of nondigital lower extremity ulcers in scleroderma and describe the associations with autoantibodies and genetic prothrombotic states. A cohort of 249 consecutive scleroderma patients seen in the Georgetown University Hosptial Division of Rheumatology was evaluated, 10 of whom had active ulcers, giving a prevalence of 4.0%. Patients with diffuse scleroderma had shorter disease duration at the time of ulcer development (mean 4.05 years ± 0.05) compared to those with limited disease (mean 22.83 years ± 5.612, P value .0078). Ulcers were bilateral in 70%. In the 10 patients with ulcers, antiphospholipid antibodies were positive in 50%, and genetic prothrombotic screen was positive in 70% which is higher than expected based on prevalence reports from the general scleroderma population. Of patients with biopsy specimens available (n = 5), fibrin occlusive vasculopathy was seen in 100%, and all of these patients had either positive antiphospholipid antibody screen, or positive genetic prothrombotic profile. We recommend screening scleroderma patients with lower extremity ulcers for the presence of anti-phospholipid antibodies and genetic prothrombotic states. PMID:20827313

  18. A dedicated cone-beam CT system for musculoskeletal extremities imaging: Design, optimization, and initial performance characterization

    SciTech Connect

    Zbijewski, W.; De Jean, P.; Prakash, P.; Ding, Y.; Stayman, J. W.; Packard, N.; Senn, R.; Yang, D.; Yorkston, J.; Machado, A.; Carrino, J. A.; Siewerdsen, J. H.

    2011-08-15

    Purpose: This paper reports on the design and initial imaging performance of a dedicated cone-beam CT (CBCT) system for musculoskeletal (MSK) extremities. The system complements conventional CT and MR and offers a variety of potential clinical and logistical advantages that are likely to be of benefit to diagnosis, treatment planning, and assessment of therapy response in MSK radiology, orthopaedic surgery, and rheumatology. Methods: The scanner design incorporated a host of clinical requirements (e.g., ability to scan the weight-bearing knee in a natural stance) and was guided by theoretical and experimental analysis of image quality and dose. Such criteria identified the following basic scanner components and system configuration: a flat-panel detector (FPD, Varian 3030+, 0.194 mm pixels); and a low-power, fixed anode x-ray source with 0.5 mm focal spot (SourceRay XRS-125-7K-P, 0.875 kW) mounted on a retractable C-arm allowing for two scanning orientations with the capability for side entry, viz. a standing configuration for imaging of weight-bearing lower extremities and a sitting configuration for imaging of tensioned upper extremity and unloaded lower extremity. Theoretical modeling employed cascaded systems analysis of modulation transfer function (MTF) and detective quantum efficiency (DQE) computed as a function of system geometry, kVp and filtration, dose, source power, etc. Physical experimentation utilized an imaging bench simulating the scanner geometry for verification of theoretical results and investigation of other factors, such as antiscatter grid selection and 3D image quality in phantom and cadaver, including qualitative comparison to conventional CT. Results: Theoretical modeling and benchtop experimentation confirmed the basic suitability of the FPD and x-ray source mentioned above. Clinical requirements combined with analysis of MTF and DQE yielded the following system geometry: a {approx}55 cm source-to-detector distance; 1.3 magnification; a

  19. A dedicated cone-beam CT system for musculoskeletal extremities imaging: Design, optimization, and initial performance characterization

    PubMed Central

    Zbijewski, W.; De Jean, P.; Prakash, P.; Ding, Y.; Stayman, J. W.; Packard, N.; Senn, R.; Yang, D.; Yorkston, J.; Machado, A.; Carrino, J. A.; Siewerdsen, J. H.

    2011-01-01

    Purpose: This paper reports on the design and initial imaging performance of a dedicated cone-beam CT (CBCT) system for musculoskeletal (MSK) extremities. The system complements conventional CT and MR and offers a variety of potential clinical and logistical advantages that are likely to be of benefit to diagnosis, treatment planning, and assessment of therapy response in MSK radiology, orthopaedic surgery, and rheumatology. Methods: The scanner design incorporated a host of clinical requirements (e.g., ability to scan the weight-bearing knee in a natural stance) and was guided by theoretical and experimental analysis of image quality and dose. Such criteria identified the following basic scanner components and system configuration: a flat-panel detector (FPD, Varian 3030+, 0.194 mm pixels); and a low-power, fixed anode x-ray source with 0.5 mm focal spot (SourceRay XRS-125-7K-P, 0.875 kW) mounted on a retractable C-arm allowing for two scanning orientations with the capability for side entry, viz. a standing configuration for imaging of weight-bearing lower extremities and a sitting configuration for imaging of tensioned upper extremity and unloaded lower extremity. Theoretical modeling employed cascaded systems analysis of modulation transfer function (MTF) and detective quantum efficiency (DQE) computed as a function of system geometry, kVp and filtration, dose, source power, etc. Physical experimentation utilized an imaging bench simulating the scanner geometry for verification of theoretical results and investigation of other factors, such as antiscatter grid selection and 3D image quality in phantom and cadaver, including qualitative comparison to conventional CT. Results: Theoretical modeling and benchtop experimentation confirmed the basic suitability of the FPD and x-ray source mentioned above. Clinical requirements combined with analysis of MTF and DQE yielded the following system geometry: a ∼55 cm source-to-detector distance; 1.3 magnification; a 20

  20. To what extent does variability of historical rainfall series influence extreme event statistics of sewer system surcharge and overflows?

    PubMed

    Schaarup-Jensen, K; Rasmussen, M R; Thorndahl, S

    2009-01-01

    In urban drainage modelling long-term extreme statistics has become an important basis for decision-making e.g. in connection with renovation projects. Therefore it is of great importance to minimize the uncertainties with regards to long-term prediction of maximum water levels and combined sewer overflow (CSO) in drainage systems. These uncertainties originate from large uncertainties regarding rainfall inputs, parameters, and assessment of return periods. This paper investigates how the choice of rainfall time series influences the extreme events statistics of max water levels in manholes and CSO volumes. Traditionally, long-term rainfall series, from a local rain gauge, are unavailable. In the present case study, however, long and local rain series are available. 2 rainfall gauges have recorded events for approximately 9 years at 2 locations within the catchment. Beside these 2 gauges another 7 gauges are located at a distance of max 20 kilometers from the catchment. All gauges are included in the Danish national rain gauge system which was launched in 1976. The paper describes to what extent the extreme events statistics based on these 9 series diverge from each other and how this diversity can be handled, e.g. by introducing an "averaging procedure" based on the variability within the set of statistics. All simulations are performed by means of the MOUSE LTS model.

  1. Between L2 and SLI: Inflections and Prepositions in the Hebrew of Bilingual Children with TLD and Monolingual Children with SLI

    ERIC Educational Resources Information Center

    Armon-Lotem, Sharon

    2014-01-01

    Verb inflectional morphology and prepositions are loci of difficulty for bilingual children with typical language development (TLD) as well as children with Specific Language Impairment (SLI). This paper examines errors in these linguistic domains in these two populations. Bilingual English-Hebrew and Russian-Hebrew preschool children, aged five…

  2. Altered architecture and enhanced drought tolerance in rice via the down-regulation of indole-3-acetic acid by TLD1/OsGH3.13 activation.

    PubMed

    Zhang, Sheng-Wei; Li, Chen-Hui; Cao, Jia; Zhang, Yong-Cun; Zhang, Su-Qiao; Xia, Yu-Feng; Sun, Da-Ye; Sun, Ying

    2009-12-01

    Plant architecture is determined by genetic and developmental programs as well as by environmental factors. Sessile plants have evolved a subtle adaptive mechanism that allows them to alter their growth and development during periods of stress. Phytohormones play a central role in this process; however, the molecules responsible for integrating growth- and stress-related signals are unknown. Here, we report a gain-of-function rice (Oryza sativa) mutant, tld1-D, characterized by (and named for) an increased number of tillers, enlarged leaf angles, and dwarfism. TLD1 is a rice GH3.13 gene that encodes indole-3-acetic acid (IAA)-amido synthetase, which is suppressed in aboveground tissues under normal conditions but which is dramatically induced by drought stress. The activation of TLD1 reduced the IAA maxima at the lamina joint, shoot base, and nodes, resulting in subsequent alterations in plant architecture and tissue patterning but enhancing drought tolerance. Accordingly, the decreased level of free IAA in tld1-D due to the conjugation of IAA with amino acids greatly facilitated the accumulation of late-embryogenesis abundant mRNA compared with the wild type. The direct regulation of such drought-inducible genes by changes in the concentration of IAA provides a model for changes in plant architecture via the process of drought adaptation, which occurs frequently in nature.

  3. Between L2 and SLI: Inflections and Prepositions in the Hebrew of Bilingual Children with TLD and Monolingual Children with SLI

    ERIC Educational Resources Information Center

    Armon-Lotem, Sharon

    2014-01-01

    Verb inflectional morphology and prepositions are loci of difficulty for bilingual children with typical language development (TLD) as well as children with Specific Language Impairment (SLI). This paper examines errors in these linguistic domains in these two populations. Bilingual English-Hebrew and Russian-Hebrew preschool children, aged five…

  4. A comparative evaluation of luminescence detectors: RPL-GD-301, TLD-100 and OSL-AL2O3:C, using Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Benali, A.-H.; Medkour Ishak-Boushaki, G.; Nourreddine, A.-M.; Allab, M.; Papadimitroulas, P.

    2017-07-01

    The luminescent dosimeters are widely used in clinical practice, for the monitoring of patient dose in external radiation therapy. Three of the most common dosimeter categories are the thermoluminescence (TLDs), the radiophotoluminescence (RPLs) and the optically stimulated luminescence (OSLs), with similar physical processes on their properties. The aim of the present study is to compare and evaluate the dosimetric properties of three specific luminescent detectors namely: a) RPL glass dosimeter, commercially known as GD-301, b) lithium fluoride TLD-100 (LiF:Mg,Ti) and c) carbon-doped aluminum oxide (Al2O3:C). For this purpose, Monte Carlo simulations were applied, using the MCNP5 code to estimate the responses of these dosimeters in terms of absorbed dose, output factor, the angular and energy dependence. In the present study, we found that the differences between the output factors were less than ± 4.2% for all detector materials RPLGD, TLD and OSLD. The variations in sensitivity for angles up to ± 80 degrees from the central axis of the beam were approximately 0.5%, 0.8% and 1.5% for the TLD-100, GD-301 and Al2O3:C, respectively. The energy dependence of the RPL and OSL dosimeters are stated as less than a 2.2%, and within 5.8% for TLD.

  5. SU-E-T-118: Dose Verification for Accuboost Applicators Using TLD, Ion Chamber and Gafchromic Film Measurements

    SciTech Connect

    Chisela, W; Yao, R; Dorbu, G

    2014-06-01

    Purpose: To verify dose delivered with HDR Accuboost applicators using TLD, ion chamber and Gafchromic film measurements and to examine applicator leakage. Methods: A microSelectron HDR unit was used to deliver a dose of 50cGy to the mid-plane of a 62mm thick solid water phantom using dwell times from Monte Carlo pre-calculated nomograms for a 60mm, 70mm Round and 60mm Skin-Dose Optimized (SDO) applicators respectively. GafChromic EBT3+ film was embedded in the phantom midplane horizontally to measure dose distribution. Absolute dose was also measured with TLDs and an ADCL calibrated parallel-plate ion chamber placed in the film plane at field center for each applicator. The film was calibrated using 6MV x-ray beam. TLDs were calibrated in a Cs-137 source at UW-Madison calibration laboratory. Radiation leakage through the tungsten alloy shell was measured with a film wrapped around outside surface of a 60mm Round applicator. Results: Measured maximum doses at field center are consistently lower than predicated by 5.8% for TLD, 8.8% for ion chamber, and 2.6% for EBT3+ film on average, with measurement uncertainties of 2.2%, 0.3%, and 2.9% for TLD, chamber, film respectively. The total standard uncertainties for ion chamber and Gafchromic film measurement are 4.9% and 4.6% respectively[1]. The area defined by the applicator aperture was covered by 80% of maximum dose for 62mm compression thickness. When 100cGy is delivered to mid-plane with a 60mm Round applicator, surface dose ranges from 60cGy to a maximum of 145cGy, which occurs at source entrance to the applicator. Conclusion: Measured doses by all three techniques are consistently lower than predicted in our measurements. For a compression thickness of 62 mm, the field size defined by the applicator is only covered by 80% of prescribed dose. Radiation leakage of up to 145cGy was found at the source entrance of applicators.

  6. Interaction of extremely-low-frequency electromagnetic fields with living systems

    SciTech Connect

    Tenforde, T.S.

    1991-11-01

    The sources and physical properties of extremely-low-frequency (ELF) electromagnetic fields are described in this paper. Biological effects and mechanisms through which ELF fields interact with humans and other organisms are discussed, including several aspects of this subject that are presently under active laboratory investigation. Studies on the potential health effects of ELF fields present in the home and workplace are also summarized, including a critical evaluation of evidence for a possible linkage between exposure to ELF fields and cancer risk. 53 refs.

  7. Complex Systems Theory to understand extremely low frequency magnetic fields interaction with immune cells

    NASA Astrophysics Data System (ADS)

    Vázquez-Coutiño, G. A.; Serrano-Luna, G.; Cañedo-Dorantes, L.; Godina-Nava, J. J.; Rodríguez-Segura, M. A.

    2003-09-01

    Well-documented studies about the interaction of extremely low frequency electromagnetic fields (ELF) with lymphocytes provide elements for the development of non-linear theoretical models. The Eichwald-Kaiser model of calcium oscillations was tested with a rectified cosine function at a frequency of 120 Hz. A change in dynamical behavior of calcium oscillations, from periodic in the normal case (without perturbation, what corresponds to a limit cycle) to the existence of very small micro-oscillations and a strange attractor in the perturbed case was found. It is concluded that the ELF configuration used in this model, alters the dynamical behavior of calcium oscillations in lymphocytes.

  8. Interaction of extremely-low-frequency electromagnetic fields with living systems

    SciTech Connect

    Tenforde, T.S.

    1991-11-01

    The sources and physical properties of extremely-low-frequency (ELF) electromagnetic fields are described in this paper. Biological effects and mechanisms through which ELF fields interact with humans and other organisms are discussed, including several aspects of this subject that are presently under active laboratory investigation. Studies on the potential health effects of ELF fields present in the home and workplace are also summarized, including a critical evaluation of evidence for a possible linkage between exposure to ELF fields and cancer risk. 53 refs.

  9. Extreme Planet-Like Systems: Brown Dwarfs at the Exoplanet Mass Boundary

    NASA Astrophysics Data System (ADS)

    Faherty, Jacqueline Kelly

    2015-12-01

    Brown dwarfs have long been the observational anchors for our theoretical understanding of giant gas planets. Recent studies have uncovered a population of nearby young sources that rival the age and mass of many planetary mass companions. From detailed observations, we postulate that objects in this young population have dynamic atmospheres ripe with exotic, thick condensate cloud species that drive extreme photometric and spectroscopic characteristics. In this talk I will review how we are using these so-called exoplanet analogs to establish luminosity, temperature, age, and mass relations for brown dwarf into planetary mass objects.

  10. Development of an early warning system for extreme rainfall, surface inundation, and malaria in East Africa

    NASA Astrophysics Data System (ADS)

    Hirt, C.; Jensen, K.; McDonald, K. C.; Ceccato, P.

    2013-12-01

    Malaria is a major health issue in Eastern Africa. In this study, we focus on rainfall and surface inundation, which are both major environmental factors in the transmission and contraction of the disease. We use the two alternative forced choice (2AFC) score and other comparative methods to analyze the efficacy of using a six-day lead precipitation forecast to predict extreme precipitation and inundation events by comparing these forecasts to historical, satellite-based precipitation and inundation observations. We also investigate the dynamics between observed surface inundation, rainfall, and malaria incidence rates in four districts of Eritrea.

  11. Multi-Scale Modeling and Probabilistic Assessment of Electrical Power and Dependent Systems' Resilience to Extreme Events

    NASA Astrophysics Data System (ADS)

    Backhaus, S.; Pasqualini, D.; Crawford, T.; Ewers, M.; Tasseff, B.; Ambrosiano, J.; Linger, S.; Roberts, R.; Bent, R.; Barnes, A.

    2016-12-01

    Electrical power systems and infrastructure systems that depend on electric power are deployed and operated at spatial scales ranging from individual facilities to cities to regions. The resilience of these systems has evolved naturally under the influence of extreme events. This evolution continues today as systems face more severe and frequent extreme events. Accurately representing the present resilience and future evolution of these systems across such a wide range of scales is both a modeling and computational challenge, especially considering that system evolution may involve new technologies and design approaches where no historical data are available to enable extrapolations. Naïve top-down aggregations of existing electrical power distribution networks will not capture important correlations between previous system hardening and critical dependent systems, leading to inaccurate modeling of current local resilience and costs associated with upgrades to improve local resilience and inaccurate boundary conditions on regional-scale electrical transmission models. Using probabilistic risk analysis approaches for hurricane and ice storm events, we present an integrated multi-scale, multi-sector modeling approach that can model and upscale naturally evolved resilience of fine-scale electrical distribution networks and their dependent critical systems. We use stochastic optimization-based models to predict and upscale potential future evolution driven by existing and emerging technologies. An optimization approach can incorporate human factors and represent potential bias in the resilience adaptation toward different residual risk profiles. We describe the coupling of these new aggregated models of fine-scale electrical power system resilience to models of regional electrical transmission systems and show how resilient regional operational strategies may be adapted to autonomous local resilience upgrades.

  12. Spatial-temporal Climate System Drivers of Australia's Total Water Storage and Vegetation Productivity under Hydroclimatic Extremes

    NASA Astrophysics Data System (ADS)

    Xie, Z.; Huete, A. R.; Ma, X.

    2016-12-01

    Extreme climate variability over Australia is driven by three dominant ocean-atmosphere climate systems including El Niño Southern Oscillation, Indian Ocean Dipole and Southern Annular Mode. In a previous study, we observed spatial clustering of Total Water Storage (TWS) responses to a Millennium drought (`big dry', 2001-09) and subsequent wet period (`big wet', 2010-11) across Australia. The entire continent partitioned into three geographic zones with diverse drying and wetting trends in rainfall, vegetation productivity, and total water storage, mimicking to varying extents, fundamental influences from the individual climate modes. We utilized Climate Index, satellite-based GRACE-Total Water Storage Anomaly (TWSA) and MODIS-Enhanced Vegetation Index (EVI) data to investigate the spatial-temporal responses, dynamics and trends of Australia's hydrologic and productivity patterns with the three climate systems. Three hydroclimatic extremes of a prolonged drought, a dramatic wet pulse and another anomalous El Niño event were analyzed from 2002 to 2015, using Partial Cross-Correlation Analyses to capture the controls of each climate driver on EVI, TWS, and rainfall. Our results confirmed the dominant influence of the climate modes and their geographic impacts on the continental scale ecohydrological patterns. Three distinct hydrologic zones in TWS patterns were observed across the hydroclimatic extremes study period, which were more pronounced than the spatial-temporal continental rainfall patterns. We further observed distinct changing patterns in surface greenness within the three zones, which were largely driven by respective Climate mode-TWS relationships, and poorly correlated with rainfall patterns. Moreover, the 2015 El Niño event, which caused severe declines in TWS and vegetation productivity over many parts of Australia, corroborated the three-zone-like influences from the climate modes. This study highlights the value of GRACE-TWSA for effectively

  13. Estimation of in-situ bioremediation system cost using a hybrid Extreme Learning Machine (ELM)-particle swarm optimization approach

    NASA Astrophysics Data System (ADS)

    Yadav, Basant; Ch, Sudheer; Mathur, Shashi; Adamowski, Jan

    2016-12-01

    In-situ bioremediation is the most common groundwater remediation procedure used for treating organically contaminated sites. A simulation-optimization approach, which incorporates a simulation model for groundwaterflow and transport processes within an optimization program, could help engineers in designing a remediation system that best satisfies management objectives as well as regulatory constraints. In-situ bioremediation is a highly complex, non-linear process and the modelling of such a complex system requires significant computational exertion. Soft computing techniques have a flexible mathematical structure which can generalize complex nonlinear processes. In in-situ bioremediation management, a physically-based model is used for the simulation and the simulated data is utilized by the optimization model to optimize the remediation cost. The recalling of simulator to satisfy the constraints is an extremely tedious and time consuming process and thus there is need for a simulator which can reduce the computational burden. This study presents a simulation-optimization approach to achieve an accurate and cost effective in-situ bioremediation system design for groundwater contaminated with BTEX (Benzene, Toluene, Ethylbenzene, and Xylenes) compounds. In this study, the Extreme Learning Machine (ELM) is used as a proxy simulator to replace BIOPLUME III for the simulation. The selection of ELM is done by a comparative analysis with Artificial Neural Network (ANN) and Support Vector Machine (SVM) as they were successfully used in previous studies of in-situ bioremediation system design. Further, a single-objective optimization problem is solved by a coupled Extreme Learning Machine (ELM)-Particle Swarm Optimization (PSO) technique to achieve the minimum cost for the in-situ bioremediation system design. The results indicate that ELM is a faster and more accurate proxy simulator than ANN and SVM. The total cost obtained by the ELM-PSO approach is held to a minimum

  14. Extreme Heat

    MedlinePlus

    ... Hurricanes Landslides & Debris Flow Nuclear Blast Nuclear Power Plants Pandemic Power Outages Radiological Dispersion Device Severe Weather Snowstorms & Extreme Cold Space Weather Thunderstorms & Lightning Tornadoes ...

  15. Modelling the dose response of peaks 4, 5 and 5b, in TLD-100, as a function of recombination temperature.

    PubMed

    Biderman, S; Oster, L; Horowitz, Y S

    2006-01-01

    This investigation focuses on whether the experimentally observed changes, in supralinearity f(D) as a function of recombination temperature, can be, successfully, predicted by the Unified Interaction Model (UNIM). To resolve this question, the measurement of f(D) has been carried out for glow peaks 4, 5 and 5b in LiF:Mg,Ti (TLD-100) at two different heating rates and UNIM analysis is used in an attempt to arrive at a consistent/physically reasonable explanation of all the f(D)/heating rate data for the three glow peaks. It is demonstrated that in addition to the variation in the luminescence and competitive centre capture cross section with temperature changes in the ks (the geminate recombination coefficient) parameter as a function of temperature is also required in order to predict the changes in f(D).

  16. Extreme Ultraviolet Solar Images Televised In-Flight with a Rocket-Borne SEC Vidicon System.

    PubMed

    Tousey, R; Limansky, I

    1972-05-01

    A TV image of the entire sun while an importance 2N solar flare was in progress was recorded in the extreme ultraviolet (XUV) radiation band 171-630 A and transmitted to ground from an Aerobee-150 rocket on 4 November 1969 using S-band telemetry. The camera tube was a Westinghouse Electric Corporation SEC vidicon, with its fiber optic faceplate coated with an XUV to visible conversion layer of p-quaterphenyl. The XUV passband was produced by three 1000-A thick aluminum filters in series together with the platinized reflecting surface of the off-axis paraboloid that imaged the sun. A number of images were recorded with integration times between 1/30 see and 2 sec. Reconstruction of pictures was enhanced by combining several to reduce the noise.

  17. Multiple-Input Multiple-Output (MIMO) Linear Systems Extreme Inputs/Outputs

    DOE PAGES

    Smallwood, David O.

    2007-01-01

    A linear structure is excited at multiple points with a stationary normal random process. The response of the structure is measured at multiple outputs. If the autospectral densities of the inputs are specified, the phase relationships between the inputs are derived that will minimize or maximize the trace of the autospectral density matrix of the outputs. If the autospectral densities of the outputs are specified, the phase relationships between the outputs that will minimize or maximize the trace of the input autospectral density matrix are derived. It is shown that other phase relationships and ordinary coherence less than one willmore » result in a trace intermediate between these extremes. Least favorable response and some classes of critical response are special cases of the development. It is shown that the derivation for stationary random waveforms can also be applied to nonstationary random, transients, and deterministic waveforms.« less

  18. Extreme inputs/outputs for multiple input multiple output linear systems.

    SciTech Connect

    Smallwood, David Ora

    2005-09-01

    A linear structure is excited at multiple points with a stationary normal random process. The response of the structure is measured at multiple outputs. If the auto spectral densities of the inputs are specified, the phase relationships between the inputs are derived that will minimize or maximize the trace of the auto spectral density matrix of the outputs. If the autospectral densities of the outputs are specified, the phase relationships between the outputs that will minimize or maximize the trace of the input auto spectral density matrix are derived. It is shown that other phase relationships and ordinary coherence less than one will result in a trace intermediate between these extremes. Least favorable response and some classes of critical response are special cases of the development. It is shown that the derivation for stationary random waveforms can also be applied to nonstationary random, transients, and deterministic waveforms.

  19. Enhanced defect detection capability using learning system for extreme ultraviolet lithography mask inspection tool with projection electron microscope optics

    NASA Astrophysics Data System (ADS)

    Hirano, Ryoichi; Hatakeyama, Masahiro; Terao, Kenji; Watanabe, Hidehiro

    2016-04-01

    Extreme ultraviolet lithography (EUVL) patterned mask defect detection is a major issue that must be addressed to realize EUVL-based device fabrication. We have designed projection electron microscope (PEM) optics for integration into a mask inspection system, and the resulting PEM system performs well in half-pitch (hp) 16-nm-node EUVL patterned mask inspection applications. A learning system has been used in this PEM patterned mask inspection tool. The PEM identifies defects using the "defectivity" parameter that is derived from the acquired image characteristics. The learning system has been developed to reduce the labor and the costs associated with adjustment of the PEM's detection capabilities to cope with newly defined mask defects. The concepts behind this learning system and the parameter optimization flow are presented here. The learning system for the PEM is based on a library of registered defects. The learning system then optimizes the detection capability by reconciling previously registered defects with newly registered defects. Functional verification of the learning system is also described, and the system's detection capability is demonstrated by applying it to the inspection of hp 11-nm EUV masks. We can thus provide a user-friendly mask inspection system with reduced cost of ownership.

  20. The ClimaGrowing Footprint of Climate Change: Can Systems Built Today Cope with Tomorrow's Weather Extremes?

    SciTech Connect

    Kintner-Meyer, Michael CW; Kraucunas, Ian P.

    2013-07-11

    This article describes how current climate conditions--with increasingly extreme storms, droughts, and heat waves and their ensuing effects on water quality and levels--are adding stress to an already aging power grid. Moreover, it explains how evaluations of said grid, built upon past weather patterns, are inaqeduate for measuring if the nation's energy systems can cope with future climate changes. The authors make the case for investing in the development of robust, integrated electricity planning tools that account for these climate change factors as a means for enhancing electricity infrastructure resilience.

  1. Spatiotemporal variability of rainfall extremes in monsoonal climates - examples from the South American Monsoon and the Indian Monsoon Systems (Invited)

    NASA Astrophysics Data System (ADS)

    Bookhagen, B.; Boers, N.; Marwan, N.; Malik, N.; Kurths, J.

    2013-12-01

    Monsoonal rainfall is the crucial component for more than half of the world's population. Runoff associated with monsoon systems provide water resources for agriculture, hydropower, drinking-water generation, recreation, and social well-being and are thus a fundamental part of human society. However, monsoon systems are highly stochastic and show large variability on various timescales. Here, we use various rainfall datasets to characterize spatiotemporal rainfall patterns using traditional as well as new approaches emphasizing nonlinear spatial correlations from a complex networks perspective. Our analyses focus on the South American (SAMS) and Indian (ISM) Monsoon Systems on the basis of Tropical Rainfall Measurement Mission (TRMM) using precipitation radar and passive-microwave products with horizontal spatial resolutions of ~5x5 km^2 (products 2A25, 2B31) and 25x25 km^2 (3B42) and interpolated rainfall-gauge data for the ISM (APHRODITE, 25x25 km^2). The eastern slopes of the Andes of South America and the southern front of the Himalaya are characterized by significant orographic barriers that intersect with the moisture-bearing, monsoonal wind systems. We demonstrate that topography exerts a first-order control on peak rainfall amounts on annual timescales in both mountain belts. Flooding in the downstream regions is dominantly caused by heavy rainfall storms that propagate deep into the mountain range and reach regions that are arid and without vegetation cover promoting rapid runoff. These storms exert a significantly different spatial distribution than average-rainfall conditions and assessing their recurrence intervals and prediction is key in understanding flooding for these regions. An analysis of extreme-value distributions of our high-spatial resolution data reveal that semi-arid areas are characterized by low-frequency/high-magnitude events (i.e., are characterized by a ';heavy tail' distribution), whereas regions with high mean annual rainfall have a

  2. Evaluation of Extremely Small Sound Source Signals Used in Speaking-Aid System with Statistical Voice Conversion

    NASA Astrophysics Data System (ADS)

    Nakamura, Keigo; Toda, Tomoki; Saruwatari, Hiroshi; Shikano, Kiyohiro

    We have so far proposed a speaking-aid system for laryngectomees using a statistical voice conversion technique. In the proposed system, artificial speech articulated with extremely small sound source signals is detected with a Non-Audible Murmur (NAM) microphone, and then, the detected artificial speech is converted into more natural voice in a probabilistic manner. Although this system basically allows laryngectomees to speak while keeping the external source signals silent, it is still questionable how much these new sound source signals affect the converted speech quality. In this paper, we investigate the impact of various sound source signals on voice conversion accuracy. Various small sound source signals are designed by changing the spectral envelope and the waveform power independently. We conduct objective and subjective evaluations. The results of these experimental evaluations demonstrate that voice conversion accepts 1) various sound source signals with different spectral envelopes and 2) large degree of power of the sound source signals unless the power of speaking parts is almost equal to that of silence parts. Moreover, we also investigate the effectiveness of enhancing auditory feedback during speaking with the extremely small sound source signals.

  3. A new absolute extreme ultraviolet image system designed for studying the radiated power of the Joint Texas Experimental Tokamak discharges

    SciTech Connect

    Zhang, J.; Zhuang, G.; Wang, Z. J.; Ding, Y. H.; Zhang, X. Q.; Tang, Y. J.

    2010-07-15

    A bolometer imaging system mounted on different toroidal and poloidal locations used for radiation observation has been developed in the Joint Texas Experimental Tokamak (J-TEXT tokamak). Three miniature pinhole AXUV16ELG (16 elements absolute extreme ultraviolet silicon photodiodes) array cameras, which are settled down in the same toroidal position but in three different poloidal places, can provide a broad viewing angle that covers the whole plasma cross-section, and hence can measure the total radiated power and provide the radiated emissive profile, while nine AXUV10EL (10 elements absolute extreme ultraviolet silicon photodiodes) array cameras are divided into three groups and will be mounted on different toroidal locations to observe the toroidal radiated power distribution. Among these detectors, one element of the AXUV16ELG array is absolutely calibrated by the synchrotron radiation source to verify the system reliability. Although there are some discrepancies between the typical responsivity given by IRD Co. and the calibrated results, it is confirmed that the discrepancies have no major effect on the final result after the simulation. The details of the system as well as observations are presented in the paper.

  4. A new absolute extreme ultraviolet image system designed for studying the radiated power of the Joint Texas Experimental Tokamak discharges.

    PubMed

    Zhang, J; Zhuang, G; Wang, Z J; Ding, Y H; Zhang, X Q; Tang, Y J

    2010-07-01

    A bolometer imaging system mounted on different toroidal and poloidal locations used for radiation observation has been developed in the Joint Texas Experimental Tokamak (J-TEXT tokamak). Three miniature pinhole AXUV16ELG (16 elements absolute extreme ultraviolet silicon photodiodes) array cameras, which are settled down in the same toroidal position but in three different poloidal places, can provide a broad viewing angle that covers the whole plasma cross-section, and hence can measure the total radiated power and provide the radiated emissive profile, while nine AXUV10EL (10 elements absolute extreme ultraviolet silicon photodiodes) array cameras are divided into three groups and will be mounted on different toroidal locations to observe the toroidal radiated power distribution. Among these detectors, one element of the AXUV16ELG array is absolutely calibrated by the synchrotron radiation source to verify the system reliability. Although there are some discrepancies between the typical responsivity given by IRD Co. and the calibrated results, it is confirmed that the discrepancies have no major effect on the final result after the simulation. The details of the system as well as observations are presented in the paper.

  5. Developing a concept of social-ecological-technological systems to characterize resilience of urban areas and infrastructure to extreme events

    NASA Astrophysics Data System (ADS)

    Chester, M.; Grimm, N. B.; Redman, C.; Miller, T.; McPherson, T.; Munoz-Erickson, T.; Chandler, D. G.

    2015-12-01

    Climate change is widely considered one of the greatest challenges to global sustainability, with extreme events being the most immediate way that people experience this phenomenon. Urban areas are particularly vulnerable to these events given their location, concentration of people, and increasingly complex and interdependent infrastructure. We are developing a conceptual framework for urban social-ecological-technological systems (SETS) that will allow researchers and practitioners to assess how infrastructure can be resilient, provide ecosystem services, improve social well being, and exploit new technologies in ways that benefit urban populations. The framework integrates the three domains of social and equity issues, environmental quality and protection, and technical/engineering aspects, to form a concept of infrastructure that occurs at the intersection of the domains. Examples show how the more common socioecological systems and socially sensitive engineering approaches that fail to incorporate the third dimension may elevate vulnerability to climate-related disaster. The SETS conceptual framework bridges currently siloed social science, environmental science, and engineering approaches to significantly advance research into the structure, function, and emergent properties of SETS. Extreme events like heat waves in Phoenix; coastal and urban flooding in the wake of superstorm Sandy and following hurricanes in Miami, FL; drought in Mexico; and urban flooding in Baltimore, Portland, San Juan PR, Syracuse, and Valdivia, Chile provide examples of the impacts of and vulnerability to extreme events that demand a new approach. The infrastructure of the future must be resilient, leverage ecosystem services, improve social well being, and exploit new technologies in ways that benefit all segments of urban populations and are appropriate to the particular urban contexts. These contexts are defined not only by the biophysical environment but also by culture and

  6. Extreme Precipitation and Emergency Room Visits for Gastrointestinal Illness in Areas With and Without Combined Sewer Systems: An Analysis of Massachusetts Data, 2003-2007

    EPA Science Inventory

    Background: Combined sewer overflows (CSOs) occur in combined sewer systems when sewage and stormwater runoff discharge into waterbodies potentially contaminating water sources. CSOs are often caused by heavy precipitation and are expected to increase with increasing extreme pre...

  7. Extreme Precipitation and Emergency Room Visits for Gastrointestinal Illness in Areas With and Without Combined Sewer Systems: An Analysis of Massachusetts Data, 2003-2007

    EPA Science Inventory

    Background: Combined sewer overflows (CSOs) occur in combined sewer systems when sewage and stormwater runoff discharge into waterbodies potentially contaminating water sources. CSOs are often caused by heavy precipitation and are expected to increase with increasing extreme pre...

  8. Recent Advances in Regional Climate System Modeling and ClimateChange Analyses of Extreme Heat

    SciTech Connect

    Miller, Norman L.

    2004-09-24

    During the period May 2003 to May 2004, there were two CEC/PIER funded primary research activities by the Atmosphere and Ocean Sciences Group/Earth Science Division at LBNL. These activities are the implementation and testing of the National Center for Atmospheric Research Community Land Model (CLM) into MM5, and the analysis of extreme heat days under a new set of climate simulations. The new version of MM5,MM5-CLM, has been tested for a 90 day snowmelt period in the northwestern U.S. Results show that this new code upgrade, as compared to the MM5-NOAH, has improved snowmelt, temperature, and precipitation when compared to observations. These are due in part to a subgrid scheme,advanced snow processes, and advanced vegetation. The climate change analysis is the upper and lower IPCC Special Report on Emission Scenarios, representing fossil fuel intensive and energy conserving future emission scenarios, and medium and low sensitivity Global Climate Models. Results indicate that California cities will see increases in the number of heat wave and temperature threshold days from two to six times.These results may be viewed as potential outcomes based on today's decisions on emissions.

  9. A Pathological Brain Detection System based on Extreme Learning Machine Optimized by Bat Algorithm.

    PubMed

    Lu, Siyuan; Qiu, Xin; Shi, Jianping; Li, Na; Lu, Zhi-Hai; Chen, Peng; Yang, Meng-Meng; Liu, Fang-Yuan; Jia, Wen-Juan; Zhang, Yudong

    2017-01-01

    It is beneficial to classify brain images as healthy or pathological automatically, because 3D brain images can generate so much information which is time consuming and tedious for manual analysis. Among various 3D brain imaging techniques, magnetic resonance (MR) imaging is the most suitable for brain, and it is now widely applied in hospitals, because it is helpful in the four ways of diagnosis, prognosis, pre-surgical, and postsurgical procedures. There are automatic detection methods; however they suffer from low accuracy. Therefore, we proposed a novel approach which employed 2D discrete wavelet transform (DWT), and calculated the entropies of the subbands as features. Then, a bat algorithm optimized extreme learning machine (BA-ELM) was trained to identify pathological brains from healthy controls. A 10x10-fold cross validation was performed to evaluate the out-of-sample performance. The method achieved a sensitivity of 99.04%, a specificity of 93.89%, and an overall accuracy of 98.33% over 132 MR brain images. The experimental results suggest that the proposed approach is accurate and robust in pathological brain detection. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  10. Rolex: Resilience-oriented language extensions for extreme-scale systems

    SciTech Connect

    Lucas, Robert F.; Hukerikar, Saurabh

    2016-05-26

    Future exascale high-performance computing (HPC) systems will be constructed from VLSI devices that will be less reliable than those used today, and faults will become the norm, not the exception. This will pose significant problems for system designers and programmers, who for half-a-century have enjoyed an execution model that assumed correct behavior by the underlying computing system. The mean time to failure (MTTF) of the system scales inversely to the number of components in the system and therefore faults and resultant system level failures will increase, as systems scale in terms of the number of processor cores and memory modules used. However every error detected need not cause catastrophic failure. Many HPC applications are inherently fault resilient. Yet it is the application programmers who have this knowledge but lack mechanisms to convey it to the system. In this paper, we present new Resilience Oriented Language Extensions (Rolex) which facilitate the incorporation of fault resilience as an intrinsic property of the application code. We describe the syntax and semantics of the language extensions as well as the implementation of the supporting compiler infrastructure and runtime system. Furthermore, our experiments show that an approach that leverages the programmer's insight to reason about the context and significance of faults to the application outcome significantly improves the probability that an application runs to a successful conclusion.

  11. Rolex: Resilience-oriented language extensions for extreme-scale systems

    DOE PAGES

    Lucas, Robert F.; Hukerikar, Saurabh

    2016-05-26

    Future exascale high-performance computing (HPC) systems will be constructed from VLSI devices that will be less reliable than those used today, and faults will become the norm, not the exception. This will pose significant problems for system designers and programmers, who for half-a-century have enjoyed an execution model that assumed correct behavior by the underlying computing system. The mean time to failure (MTTF) of the system scales inversely to the number of components in the system and therefore faults and resultant system level failures will increase, as systems scale in terms of the number of processor cores and memory modulesmore » used. However every error detected need not cause catastrophic failure. Many HPC applications are inherently fault resilient. Yet it is the application programmers who have this knowledge but lack mechanisms to convey it to the system. In this paper, we present new Resilience Oriented Language Extensions (Rolex) which facilitate the incorporation of fault resilience as an intrinsic property of the application code. We describe the syntax and semantics of the language extensions as well as the implementation of the supporting compiler infrastructure and runtime system. Furthermore, our experiments show that an approach that leverages the programmer's insight to reason about the context and significance of faults to the application outcome significantly improves the probability that an application runs to a successful conclusion.« less

  12. Rolex: Resilience-oriented language extensions for extreme-scale systems

    SciTech Connect

    Lucas, Robert F.; Hukerikar, Saurabh

    2016-05-26

    Future exascale high-performance computing (HPC) systems will be constructed from VLSI devices that will be less reliable than those used today, and faults will become the norm, not the exception. This will pose significant problems for system designers and programmers, who for half-a-century have enjoyed an execution model that assumed correct behavior by the underlying computing system. The mean time to failure (MTTF) of the system scales inversely to the number of components in the system and therefore faults and resultant system level failures will increase, as systems scale in terms of the number of processor cores and memory modules used. However every error detected need not cause catastrophic failure. Many HPC applications are inherently fault resilient. Yet it is the application programmers who have this knowledge but lack mechanisms to convey it to the system. In this paper, we present new Resilience Oriented Language Extensions (Rolex) which facilitate the incorporation of fault resilience as an intrinsic property of the application code. We describe the syntax and semantics of the language extensions as well as the implementation of the supporting compiler infrastructure and runtime system. Furthermore, our experiments show that an approach that leverages the programmer's insight to reason about the context and significance of faults to the application outcome significantly improves the probability that an application runs to a successful conclusion.

  13. Microorganisms in extreme environments with a view to astrobiology in the outer solar system

    NASA Astrophysics Data System (ADS)

    Seckbach, Joseph; Chela-Flores, Julian

    2015-09-01

    We review the various manifestations of the evolution of life in extreme environments. We review those aspects of extremophiles that are most relevant for astrobiology. We are aware that geothermal energy triggering sources of heat in oceanic environments are not unique to our planet, a fact that was exposed by the Voyager mission images of volcanic activity on Io, the Jovian moon. Such activity exceeded by far what was known form terrestrial geology. The science of astrobiology has considered the possible presence of several moon oceans in the vicinity of both giant gas and icy planets. These watery environments include, not only Europa (strongly suggested by data from the Galileo mission), but the Voyager flybys exposed, not only the unusual geothermal activity on Io, but also the possible presence of subsurface oceans and some geothermal activity on the Neptune's moon Triton. More recently, calculations of Hussmann and coworkers with available data do not exclude that even Uranus moons may be candidates for bearing subsurface oceans. These possibilities invite a challenge that we gladly welcome, of preliminary discussions of habitability of extremophiles in so far novel environments for the science of astrobiology. Nevertheless, such exploration is currently believed to be feasible with the new generations of missions suggested for the time window of 2030 - 2040, or even earlier. We are envisaging, not only the current exploration of the moons of Saturn, but in the coming years we expect to go beyond to Uranus and Neptune to include dwarf planets and trans-neptunian worlds. Consequently, it is necessary to begin questioning whether the Europa-like conditions for the evolution of microorganisms are repeatable elsewhere. At present three new missions are in the process of being formulated, including the selection of payloads that will be necessary for the exploration of the various so far unexplored moons.

  14. Extremely short impulse eddy current system for titanium and inconel samples testing

    SciTech Connect

    Chady, T.; Frankowski, P.

    2011-06-23

    This paper presents a new system for eddy current testing. The system enables tests with very short current impulses. Therefore, the frequency spectrum of the excitation signal is very wide. In this paper, a study of eddy current differential transducer for testing titanium element is also presented.

  15. Development of body weight support gait training system using pneumatic Mckibben actuators -control of lower extremity orthosis.

    PubMed

    Mat Dzahir, M A; Nobutomo, T; Yamamoto, S I

    2013-01-01

    Recently, robot assisted therapy devices are increasingly used for spinal cord injury (SCI) rehabilitation in assisting handicapped patients to regain their impaired movements. Assistive robotic systems may not be able to cure or fully compensate impairments, but it should be able to assist certain impaired functions and ease movements. In this study, the control system of lower extremity orthosis for the body weight support gait training system which implements pneumatic artificial muscle (PAM) is proposed. The hip and knee joint angles of the gait orthosis system are controlled based on the PAM coordinates information from the simulation. This information provides the contraction data for the mono- and bi-articular PAMs that are arranged as posterior and anterior actuators to simulate the human walking motion. The proposed control system estimates the actuators' contraction as a function of hip and knee joint angles. Based on the contraction model obtained, input pressures for each actuators are measured. The control system are performed at different gait cycles and two PMA settings for the mono- and bi-articular actuators are evaluated in this research. The results showed that the system was able to achieve the maximum muscle moment at the joints, and able to perform the heel contact movement. This explained that the antagonistic mono- and bi-articular actuators worked effectively.

  16. Validation of the Microsoft Kinect® camera system for measurement of lower extremity jump landing and squatting kinematics.

    PubMed

    Eltoukhy, Moataz; Kelly, Adam; Kim, Chang-Young; Jun, Hyung-Pil; Campbell, Richard; Kuenze, Christopher

    2016-01-01

    Cost effective, quantifiable assessment of lower extremity movement represents potential improvement over standard tools for evaluation of injury risk. Ten healthy participants completed three trials of a drop jump, overhead squat, and single leg squat task. Peak hip and knee kinematics were assessed using an 8 camera BTS Smart 7000DX motion analysis system and the Microsoft Kinect® camera system. The agreement and consistency between both uncorrected and correct Kinect kinematic variables and the BTS camera system were assessed using interclass correlations coefficients. Peak sagittal plane kinematics measured using the Microsoft Kinect® camera system explained a significant amount of variance [Range(hip) = 43.5-62.8%; Range(knee) = 67.5-89.6%] in peak kinematics measured using the BTS camera system. Across tasks, peak knee flexion angle and peak hip flexion were found to be consistent and in agreement when the Microsoft Kinect® camera system was directly compared to the BTS camera system but these values were improved following application of a corrective factor. The Microsoft Kinect® may not be an appropriate surrogate for traditional motion analysis technology, but it may have potential applications as a real-time feedback tool in pathological or high injury risk populations.

  17. Extreme ultraviolet patterned mask inspection performance of advanced projection electron microscope system for 11nm half-pitch generation

    NASA Astrophysics Data System (ADS)

    Hirano, Ryoichi; Iida, Susumu; Amano, Tsuyoshi; Watanabe, Hidehiro; Hatakeyama, Masahiro; Murakami, Takeshi; Suematsu, Kenichi; Terao, Kenji

    2016-03-01

    Novel projection electron microscope optics have been developed and integrated into a new inspection system named EBEYE-V30 ("Model EBEYE" is an EBARA's model code) , and the resulting system shows promise for application to half-pitch (hp) 16-nm node extreme ultraviolet lithography (EUVL) patterned mask inspection. To improve the system's inspection throughput for 11-nm hp generation defect detection, a new electron-sensitive area image sensor with a high-speed data processing unit, a bright and stable electron source, and an image capture area deflector that operates simultaneously with the mask scanning motion have been developed. A learning system has been used for the mask inspection tool to meet the requirements of hp 11-nm node EUV patterned mask inspection. Defects are identified by the projection electron microscope system using the "defectivity" from the characteristics of the acquired image. The learning system has been developed to reduce the labor and costs associated with adjustment of the detection capability to cope with newly-defined mask defects. We describe the integration of the developed elements into the inspection tool and the verification of the designed specification. We have also verified the effectiveness of the learning system, which shows enhanced detection capability for the hp 11-nm node.

  18. An Adaptive Simulation Framework for the Exploration of Extreme and Unexpected Events in Dynamic Engineered Systems.

    PubMed

    Turati, Pietro; Pedroni, Nicola; Zio, Enrico

    2017-01-01

    The end states reached by an engineered system during an accident scenario depend not only on the sequences of the events composing the scenario, but also on their timing and magnitudes. Including these additional features within an overarching framework can render the analysis infeasible in practical cases, due to the high dimension of the system state-space and the computational effort correspondingly needed to explore the possible system evolutions in search of the interesting (and very rare) ones of failure. To tackle this hurdle, in this article we introduce a framework for efficiently probing the space of event sequences of a dynamic system by means of a guided Monte Carlo simulation. Such framework is semi-automatic and allows embedding the analyst's prior knowledge about the system and his/her objectives of analysis. Specifically, the framework allows adaptively and intelligently allocating the simulation efforts preferably on those sequences leading to outcomes of interest for the objectives of the analysis, e.g., typically those that are more safety-critical (and/or rare). The emerging diversification in the filling of the state-space by the preference-guided exploration allows also the retrieval of critical system features, which can be useful to analysts and designers for taking appropriate means of prevention and mitigation of dangerous and/or unexpected consequences. A dynamic system for gas transmission is considered as a case study to demonstrate the application of the method.

  19. Past exposure to climate extremes can inform future projections and guide management: coral reefs as a model system

    NASA Astrophysics Data System (ADS)

    Donner, S. D.

    2016-12-01

    Coral reefs are thought to be more sensitive to climate change than any other marine ecosystem. Episodes of mass coral bleaching, due to anomalously warm water temperatures, have led to coral mortality, declines in coral cover and shifts in the population of other reef-dwelling organisms. The onset of mass bleaching is typically predicted using accumulated heat stress, specifically when the SST exceeds a local climatological maximum by 1-2 °C for a month or more. However, recent evidence suggests that the threshold at which bleaching occurs depends on the past thermal experience of the coral reef and the composition of the coral community. This presentation describes the results of a long-term field and modelling research program evaluating the influence of climate experience on the susceptibility of coral reef ecosystems to future climate extremes. Modeling work identified Kiribati's equatorial Gilbert Islands, where the El Niño / Southern Oscillation drives year-to-year shifts in current strength, current direction and consequently ocean temperatures, as an ideal natural laboratory for studying ocean climate extremes. The field program then tracked changes in the coral communities over multiple heat stress events (e.g. 2004-5, 2009-10 El Niño) at a matrix of sites exposed to different levels of historical climate variability and human disturbance. Among the results is evidence that coral bleaching patterns are best predicted by the coefficient of variation of past SST, light exposure, and the presence of particular resilient coral taxa, rather than the standard heat stress metrics. The lessons of this research can be applicable other systems where past experience influences the response to climate extremes

  20. Addition of magnetic field capability to existing extremely-low-frequency electric field exposure systems.

    PubMed

    Miller, D L; Miller, M C; Kaune, W T

    1989-01-01

    Magnetic field systems were added to existing electric field exposure apparatuses for exposing cell suspensions in vitro and small animals in vivo. Two horizontally oriented, rectangular coils, stacked one directly above the other, have opposite electric currents. This configuration minimizes leakage fields and allows sham- and field-exposure systems to be placed in the same room or incubator. For the in vitro system, copper plates formed the loop-pair, with up to 900 A supplied by a 180:1 transformer. Electric fields were supplied via electrodes at the ends of cell-culture tubes, eight of which can be accommodated by each exposure system. Two complete systems are situated in an incubator to allow simultaneous sham and field exposure up to 1 mT. For the in vivo system, four pairs of 0.8 x 2.7-m coils made of copper bus bar are employed. This arrangement is energized from the power grid via a 30:1 transformer; horizontal magnetic flux densities up to 1 mT can be generated. Pairs of electrode plates spaced 30.5 cm apart provide electric field exposure of up to 130 kV/m. Four systems with a capacity of 48 rats each are located in one room. For both the in vitro and in vivo systems, magnetic exposure fields are uniform to within +/- 2.5%, and sham levels are at least 2,500-fold lower than exposure levels. Potential confounding factors, such as heating and vibration, were examined and found to be minimal.

  1. A Photo-Realistic 3-D Mapping System for Extreme Nuclear Environments: Chornobyl

    NASA Technical Reports Server (NTRS)

    Maimone, M.; Matthies, L.; Osborn, J.; Teza, J.; Thayer, S.

    1998-01-01

    We present a novel stereoscopic mapping system for use in nuclear accident settings. First we discuss a radiation shielded sensor array desigtned to tolerate 10(sup 6)R of cumulative dose. Next we give procedures to ensure timely, accurate range estimation using trinocular stereo. Finally, we review the implementation of a system for the integration of range information into a 3-D, textured, metrically accurate surface mesh.

  2. A radar-based regional extreme rainfall analysis to derive the thresholds for a novel automatic alert system in Switzerland

    NASA Astrophysics Data System (ADS)

    Panziera, Luca; Gabella, Marco; Zanini, Stefano; Hering, Alessandro; Germann, Urs; Berne, Alexis

    2016-06-01

    This paper presents a regional extreme rainfall analysis based on 10 years of radar data for the 159 regions adopted for official natural hazard warnings in Switzerland. Moreover, a nowcasting tool aimed at issuing heavy precipitation regional alerts is introduced. The two topics are closely related, since the extreme rainfall analysis provides the thresholds used by the nowcasting system for the alerts. Warm and cold seasons' monthly maxima of several statistical quantities describing regional rainfall are fitted to a generalized extreme value distribution in order to derive the precipitation amounts corresponding to sub-annual return periods for durations of 1, 3, 6, 12, 24 and 48 h. It is shown that regional return levels exhibit a large spatial variability in Switzerland, and that their spatial distribution strongly depends on the duration of the aggregation period: for accumulations of 3 h and shorter, the largest return levels are found over the northerly alpine slopes, whereas for longer durations the southern Alps exhibit the largest values. The inner alpine chain shows the lowest values, in agreement with previous rainfall climatologies. The nowcasting system presented here is aimed to issue heavy rainfall alerts for a large variety of end users, who are interested in different precipitation characteristics and regions, such as, for example, small urban areas, remote alpine catchments or administrative districts. The alerts are issued not only if the rainfall measured in the immediate past or forecast in the near future exceeds some predefined thresholds but also as soon as the sum of past and forecast precipitation is larger than threshold values. This precipitation total, in fact, has primary importance in applications for which antecedent rainfall is as important as predicted one, such as urban floods early warning systems. The rainfall fields, the statistical quantity representing regional rainfall and the frequency of alerts issued in case of

  3. An Expert Diagnosis System for Parkinson Disease Based on Genetic Algorithm-Wavelet Kernel-Extreme Learning Machine.

    PubMed

    Avci, Derya; Dogantekin, Akif

    2016-01-01

    Parkinson disease is a major public health problem all around the world. This paper proposes an expert disease diagnosis system for Parkinson disease based on genetic algorithm- (GA-) wavelet kernel- (WK-) Extreme Learning Machines (ELM). The classifier used in this paper is single layer neural network (SLNN) and it is trained by the ELM learning method. The Parkinson disease datasets are obtained from the UCI machine learning database. In wavelet kernel-Extreme Learning Machine (WK-ELM) structure, there are three adjustable parameters of wavelet kernel. These parameters and the numbers of hidden neurons play a major role in the performance of ELM. In this study, the optimum values of these parameters and the numbers of hidden neurons of ELM were obtained by using a genetic algorithm (GA). The performance of the proposed GA-WK-ELM method is evaluated using statical methods such as classification accuracy, sensitivity and specificity analysis, and ROC curves. The calculated highest classification accuracy of the proposed GA-WK-ELM method is found as 96.81%.

  4. High numerical aperture ring field projection system for extreme ultraviolet lithography

    DOEpatents

    Hudyma, Russell; Shafer, David

    2001-01-01

    An all-reflective optical system for a projection photolithography camera has a source of EUV radiation, a wafer and a mask to be imaged on the wafer. The optical system includes a first convex mirror, a second mirror, a third convex mirror, a fourth concave mirror, a fifth convex mirror and a sixth concave mirror. The system is configured such that five of the six mirrors receives a chief ray at an incidence angle of less than substantially 9.degree., and each of the six mirrors receives a chief ray at an incidence angle of less than substantially 14.degree.. Four of the six reflecting surfaces have an aspheric departure of less than substantially 12 .mu.m. Five of the six reflecting surfaces have an aspheric departure of less than substantially 12 .mu.m. Each of the six reflecting surfaces has an aspheric departure of less than substantially 16 .mu.m.

  5. High numerical aperture ring field projection system for extreme ultraviolet lithography

    DOEpatents

    Hudyma, Russell; Shafer, David R.

    2001-01-01

    An all-reflective optical system for a projection photolithography camera has a source of EUV radiation, a wafer and a mask to be imaged on the wafer. The optical system includes a first convex mirror, a second mirror, a third convex mirror, a fourth concave mirror, a fifth convex mirror and a sixth concave mirror. The system is configured such that five of the six mirrors receive a chief ray at an incidence angle of less than substantially 9.degree., and each of the six mirrors receives a chief ray at an incidence angle of less than substantially 14.degree.. Four of the six reflecting surfaces have an aspheric departure of less than substantially 12 .mu.m. Five of the six reflecting surfaces have an aspheric departure of less than substantially 12 .mu.m. Each of the six reflecting surfaces has an aspheric departure of less than substantially 16 .mu.m.

  6. High numerical aperture ring field projection system for extreme ultraviolet lithography

    DOEpatents

    Hudyma, Russell

    2001-01-01

    An all-reflective optical system for a projection photolithography camera has a source of EUV radiation, a wafer and a mask to be imaged on the wafer. The optical system includes a first concave mirror, a second mirror, a third convex mirror, a fourth concave mirror, a fifth convex mirror and a sixth concave mirror. The system is configured such that five of the six mirrors receives a chief ray at an incidence angle of less than substantially 12.degree., and each of the six mirrors receives a chief ray at an incidence angle of less than substantially 15.degree.. Four of the six reflecting surfaces have an aspheric departure of less than substantially 7 .mu.m. Five of the six reflecting surfaces have an aspheric departure of less than substantially 14 .mu.m. Each of the six reflecting surfaces has an aspheric departure of less than 16.0 .mu.m.

  7. High numerical aperture ring field projection system for extreme ultraviolet lithography

    DOEpatents

    Hudyma, Russell

    2000-01-01

    An all-refelctive optical system for a projection photolithography camera has a source of EUV radiation, a wafer and a mask to be imaged on the wafer. The optical system includes a first concave mirror, a second mirror, a third convex mirror, a fourth concave mirror, a fifth convex mirror and a sixth concave mirror. The system is configured such that five of the six mirrors receives a chief ray at an incidence angle less than substantially 12.degree., and each of the six mirrors receives a chief ray at an incidence angle of less than substantially 15.degree.. Four of the six reflecting surfaces have an aspheric departure of less than substantially 7 .mu.m. Five of the six reflecting surfaces have an aspheric departure of less than substantially 14 .mu.m. Each of the six refelecting surfaces has an aspheric departure of less than 16.0 .mu.m.

  8. Extreme Quantum Advantage when Simulating Classical Systems with Long-Range Interaction.

    PubMed

    Aghamohammadi, Cina; Mahoney, John R; Crutchfield, James P

    2017-07-27

    Classical stochastic processes can be generated by quantum simulators instead of the more standard classical ones, such as hidden Markov models. One reason for using quantum simulators has recently come to the fore: they generally require less memory than their classical counterparts. Here, we examine this quantum advantage for strongly coupled spin systems-in particular, the Dyson one-dimensional Ising spin chain with variable interaction length. We find that the advantage scales with both interaction range and temperature, growing without bound as interaction range increases. In particular, simulating Dyson's original spin chain with the most memory-efficient classical algorithm known requires infinite memory, while a quantum simulator requires only finite memory. Thus, quantum systems can very efficiently simulate strongly coupled one-dimensional classical spin systems.

  9. High numerical aperture ring field projection system for extreme ultraviolet lithography

    DOEpatents

    Hudyma, Russell

    2001-01-01

    An all-reflective optical system for a projection photolithography camera has a source of EUV radiation, a wafer and a mask to be imaged on the wafer. The optical system includes a first concave mirror, a second mirror, a third convex mirror, a fourth concave mirror, a fifth convex mirror and a sixth concave mirror. The system is configured such that five of the six mirrors receives a chief ray at an incidence angle of less than substantially 12.degree., and each of the six mirrors receives a chief ray at an incidence angle of less than substantially 15.degree.. Four of the six reflecting surfaces have an aspheric departure of less than substantially 7 .mu.m. Five of the six reflecting surfaces have an aspheric departure of less than substantially 14 .mu.m. Each of the six reflecting surfaces has an aspheric departure of less than 16.0 .mu.m.

  10. Systemic Inflammation Associated with Severe Intestinal Injury in Extremely Low Gestational Age Newborns

    PubMed Central

    Martin, Camilia R.; Bellomy, Melissa; Allred, Elizabeth N.; Fichorova, Raina N.; Leviton, Alan

    2014-01-01

    To define the role of systemic inflammation in infants with intestinal perforation (IP) and necrotizing enterocolitis (NEC), we measured 25 blood protein concentrations on days 1, 7, and 14 in 939 infants born before 28 weeks’ gestation. On days 7 and 14, infants with NEC had elevated levels of CRP, serum amyloid A (SAA), IL-6, and IL-8. Infants with IP had elevated levels of CRP and insulin growth factor binding protein-1 on day 7 and elevated CRP, SAA, TNF-receptor-2, and matrix metalloproteinase-9 levels on day 14. A better understanding of systemic inflammation might help prevent and treat these disorders. PMID:23002960

  11. Freeing the foot: integrating the foot core system into rehabilitation for lower extremity injuries.

    PubMed

    McKeon, Patrick O; Fourchet, François

    2015-04-01

    The intrinsic muscles of the foot play a critical role in the regulation of absorption and propulsion during dynamic activities. Dysfunction of these may lead to an increased demand on the remaining components within the foot core system to maintain dynamic foot control, leading to a more rapid breakdown of these contributors and those proximal to the foot. Training the intrinsic foot muscles through a systematic progression of isolation via the short foot exercise offers the opportunity to reincorporate their contribution into the foot core system. This article discusses the function of the intrinsic foot muscles, their contributions to dynamic foot control, and a progressive training paradigm.

  12. Susceptibility of South Korea to Extremes Affecting the Global Food System

    NASA Technical Reports Server (NTRS)

    Chon, So Young; Puma, Michael J.

    2015-01-01

    Food security in South Korea is tightly linked to the global food system. The country's production of major grains declined from 5.8 million metric tons (mmt) in 1998 to 4.8 mmt in 2014, which caused the country's grain self suciency to decline from 31.4% to 24%. This decline is a consequence of several factors including reductions in domestic agricultural land, governmental policies supporting industry over agriculture, and a push towards trade liberalization. South Korea's self suciency is now one of the lowest among Organisation for Economic Co-operation and Development (OECD) countries, leaving it vulnerable to disruptions in the global food system.

  13. Landsat and GRACE observations of arid wetland dynamics in a dryland river system under multi-decadal hydroclimatic extremes

    NASA Astrophysics Data System (ADS)

    Xie, Zunyi; Huete, Alfredo; Ma, Xuanlong; Restrepo-Coupe, Natalia; Devadas, Rakhesh; Clarke, Kenneth; Lewis, Megan

    2016-12-01

    Arid wetlands are important for biodiversity conservation, but sensitive and vulnerable to climate variability and hydroclimatic events. Amplification of the water cycle, including the increasing frequency and severity of droughts and wet extremes, is expected to alter spatial and temporal hydrological patterns in arid wetlands globally, with potential threats to ecosystem services and their functioning. Despite these pressing challenges, the ecohydrological interactions and resilience of arid wetlands to highly variable water regimes over long time periods remain largely unknown. Recent broad-scale drought and floods over Australia provide unique opportunities to improve our understanding of arid wetland ecosystem responses to hydroclimatic extremes. Here we analysed the ecohydrological dynamics of the Coongie Lakes arid wetland in central Australia, one of the world's largest Ramsar-designated wetlands, using more than two decades (1988-2011) of vegetation and floodwater extent retrievals derived from Landsat satellite observations. To explore the impacts of large-scale hydrological fluctuations on the arid wetland, we further coupled Landsat measurements with Total Water Storage Anomaly (TWSA) data obtained from the Gravity Recovery and Climate Experiment (GRACE) satellites. Pronounced seasonal and inter-annual variabilities of flood and vegetation activities were observed over the wetland, with variations in vegetation growth extent highly correlated with flood extent (r = 0.64, p < 0.05) that ranged from nearly zero to 3456 km2. We reported the hydrological dynamics and associated ecosystem responses to be largely driven by the two phases (El Niño and La Niña) of the El Nino-Southern Oscillation (ENSO) ocean-atmosphere system. Changes in flood and vegetation extent were better explained by GRACE-TWSA (r = 0.8, lag = 0 month) than rainfall (r = 0.34, lag = 3 months) over the water source area, demonstrating that TWS is a valuable hydrological indicator for

  14. Adaptation of the vascular system to extremal factors. [acceleration stress and tolerance

    NASA Technical Reports Server (NTRS)

    Prives, M. G.

    1975-01-01

    Exposure to g-forces causes changes in the vascular systems of animals. The vessels are distorted and their contents may escape. Various parts of a given organ may react differently according to their structure, and arteries will undergo changes that depend on their position relative to the direction of the g-force vector.

  15. Gesture therapy: a vision-based system for upper extremity stroke rehabilitation.

    PubMed

    Sucar, L; Luis, Roger; Leder, Ron; Hernandez, Jorge; Sanchez, Israel

    2010-01-01

    Stroke is the main cause of motor and cognitive disabilities requiring therapy in the world. Therefor it is important to develop rehabilitation technology that allows individuals who had suffered a stroke to practice intensive movement training without the expense of an always-present therapist. We have developed a low-cost vision-based system that allows stroke survivors to practice arm movement exercises at home or at the clinic, with periodic interactions with a therapist. The system integrates a virtual environment for facilitating repetitive movement training, with computer vision algorithms that track the hand of a patient, using an inexpensive camera and a personal computer. This system, called Gesture Therapy, includes a gripper with a pressure sensor to include hand and finger rehabilitation; and it tracks the head of the patient to detect and avoid trunk compensation. It has been evaluated in a controlled clinical trial at the National Institute for Neurology and Neurosurgery in Mexico City, comparing it with conventional occupational therapy. In this paper we describe the latest version of the Gesture Therapy System and summarize the results of the clinical trail.

  16. Linkages between Families and Political Extremism: A Theory of the Authoritarian Personality and Family System Dynamics.

    ERIC Educational Resources Information Center

    Gaziano, Cecilie

    This paper seeks to integrate some ideas from family systems theory and attachment theory within a theory of public opinion and social movement. Citing the classic "The Authoritarian Personality," the paper states that the first authorities children know, their parents or other caregivers, shape children's attitudes toward all…

  17. Effect of a magnetic field of extremely low intensity on the coagulatory system of the blood

    NASA Technical Reports Server (NTRS)

    Zabrodina, L. V.

    1974-01-01

    The influence of a magnetic field of 10,000 gamma on the conditions of the coagulatory system of rabbits was studied. The results from a number of experiments indicate that the action of a very weak magnetic field produces an increase in the coagulatory activity of the blood.

  18. Adaptation of the vascular system to extremal factors. [acceleration stress and tolerance

    NASA Technical Reports Server (NTRS)

    Prives, M. G.

    1975-01-01

    Exposure to g-forces causes changes in the vascular systems of animals. The vessels are distorted and their contents may escape. Various parts of a given organ may react differently according to their structure, and arteries will undergo changes that depend on their position relative to the direction of the g-force vector.

  19. Bivariate extreme value distributions

    NASA Technical Reports Server (NTRS)

    Elshamy, M.

    1992-01-01

    In certain engineering applications, such as those occurring in the analyses of ascent structural loads for the Space Transportation System (STS), some of the load variables have a lower bound of zero. Thus, the need for practical models of bivariate extreme value probability distribution functions with lower limits was identified. We discuss the Gumbel models and present practical forms of bivariate extreme probability distributions of Weibull and Frechet types with two parameters. Bivariate extreme value probability distribution functions can be expressed in terms of the marginal extremel distributions and a 'dependence' function subject to certain analytical conditions. Properties of such bivariate extreme distributions, sums and differences of paired extremals, as well as the corresponding forms of conditional distributions, are discussed. Practical estimation techniques are also given.

  20. Short-Term Distribution System State Forecast Based on Optimal Synchrophasor Sensor Placement and Extreme Learning Machine

    SciTech Connect

    Jiang, Huaiguang; Zhang, Yingchen

    2016-11-14

    This paper proposes an approach for distribution system state forecasting, which aims to provide an accurate and high speed state forecasting with an optimal synchrophasor sensor placement (OSSP) based state estimator and an extreme learning machine (ELM) based forecaster. Specifically, considering the sensor installation cost and measurement error, an OSSP algorithm is proposed to reduce the number of synchrophasor sensor and keep the whole distribution system numerically and topologically observable. Then, the weighted least square (WLS) based system state estimator is used to produce the training data for the proposed forecaster. Traditionally, the artificial neural network (ANN) and support vector regression (SVR) are widely used in forecasting due to their nonlinear modeling capabilities. However, the ANN contains heavy computation load and the best parameters for SVR are difficult to obtain. In this paper, the ELM, which overcomes these drawbacks, is used to forecast the future system states with the historical system states. The proposed approach is effective and accurate based on the testing results.

  1. Wireless wearable range-of-motion sensor system for upper and lower extremity joints: a validation study

    PubMed Central

    Kumar, Yogaprakash; Yen, Shih-Cheng; Lee, Wangwei; Gao, Fan; Zhao, Ziyi; Li, Jingze; Hon, Benjamin; Tian-Ma Xu, Tim; Cheong, Angela; Koh, Karen; Ng, Yee-Sien; Chew, Effie; Koh, Gerald

    2015-01-01

    Range-of-motion (ROM) assessment is a critical assessment tool during the rehabilitation process. The conventional approach uses the goniometer which remains the most reliable instrument but it is usually time-consuming and subject to both intra- and inter-therapist measurement errors. An automated wireless wearable sensor system for the measurement of ROM has previously been developed by the current authors. Presented is the correlation and accuracy of the automated wireless wearable sensor system against a goniometer in measuring ROM in the major joints of upper (UEs) and lower extremities (LEs) in 19 healthy subjects and 20 newly disabled inpatients through intra (same) subject comparison of ROM assessments between the sensor system against goniometer measurements by physical therapists. In healthy subjects, ROM measurements using the new sensor system were highly correlated with goniometry, with 95% of differences < 20° and 10° for most movements in major joints of UE and LE, respectively. Among inpatients undergoing rehabilitation, ROM measurements using the new sensor system were also highly correlated with goniometry, with 95% of the differences being < 20° and 25° for most movements in the major joints of UE and LE, respectively. PMID:26609398

  2. Award ER25844: Minimizing System Noise Effects for Extreme-Scale Scientific Simulation Through Function Delegation

    SciTech Connect

    Lumsdaine, Andrew

    2012-11-20

    In software running on distributed computing clusters, time spent on communication between nodes in the cluster can be a significant portion of the overall computation time; background operating system tasks and other computational noise on the nodes of the system can have a significant impact on the amount of time this communication takes, especially on large systems. The research completed in this period has improved understanding of when such noise will have a significant impact. Specifically, it was demonstrated that not just noise on the nodes, but also noise on the network between nodes can have a significant impact on computation time. It was also demonstrated that noise patterns matter more than noise intensity: very regular noise can cause less disruption than lighter (on average) but less regular noise. It was also demonstrated that the effect of noise is more prominent as the speed of the network between nodes is increased. Furthermore, a tracing tool, Netgauge, was improved via our work, and a system simulator, LogGOPSim, was developed; they can be used by application developers to improve performance of their program and by system designers to mitigate the effects of noise by adjusting the noise characteristics of the operating system. Both have been made freely available as open source programs. In the course of developing these tools, we demonstrated weaknesses in existing methodologies for modeling communication, and we introduced a more detailed model, LogGOPS, for simulating systems. Not only were the deleterious effects of noise explored but we have also offered solutions. Our studies of simulations of system noise have led to specific recommendations on tuning systems to mitigate noise. We have also improved existing approaches to mitigating noise. Non-blocking collective communication avoids the effects of noise by letting communication continue simultaneously with computation (thus being non-blocking), so that the delays in communication

  3. Extremely Low Frequency (ELF) communications system ecological monitoring program. Summary of 1984 progress

    NASA Astrophysics Data System (ADS)

    Zapotosky, J. E.

    1985-07-01

    A long-term program is being conducted to monitor for possible effects from the operation of the U.S. Navy's ELF Communications System to resident biota and their ecological relationships. Monitoring studies were selected through a peer-reviewed, competitive bidding process in mid-1982; studies were initiated in late summer of that year. Currently, 16 general types of organisms from three major ecosystems in the ELF Communications System are being examined. During 1984, the Program continued and extended those major activities initiated in 1983, consisting of site selection, the characterization of critical study aspects, and, to a lesser degree, the validation of assumptions made in the original proposals. Progress is summarized for the 11 projects that comprise the Program as well as for the support activities of IIT Research Institute.

  4. Design and Implementation of Broadcast Algorithms for Extreme-Scale Systems

    SciTech Connect

    Shamis, Pavel; Graham, Richard L; Gorentla Venkata, Manjunath; Ladd, Joshua

    2011-01-01

    The scalability and performance of collective communication operations limit the scalability and performance of many scientific applications. This paper presents two new blocking and nonblocking Broadcast algorithms for communicators with arbitrary communication topology, and studies their performance. These algorithms benefit from increased concurrency and a reduced memory footprint, making them suitable for use on large-scale systems. Measuring small, medium, and large data Broadcasts on a Cray-XT5, using 24,576 MPI processes, the Cheetah algorithms outperform the native MPI on that system by 51%, 69%, and 9%, respectively, at the same process count. These results demonstrate an algorithmic approach to the implementation of the important class of collective communications, which is high performing, scalable, and also uses resources in a scalable manner.

  5. Water-biomolecule systems under extreme conditions: from confinement to pressure effects

    NASA Astrophysics Data System (ADS)

    Bellissent-Funel, M.-C.

    Water is a unique liquid, many of whose properties are critical for the continued support of life. In living systems, essential water-related phenomena occur in restricted geometries in cells, and at active sites of proteins and membranes or at their surface. The effects of hydration on equilibrium protein structure and dynamics are fundamental to the relationship between structure and biological function. In particular, the configuration of water molecules near the hydrophilic-hydrophobic interfaces is of considerable relevance. The structure and dynamics of water confined in model systems developing hydrophilic interactions are compared with that of bulk water as determined by hydrophilic interactions are compared with that of bulk water as determined by neutron scattering. It is well known that hydration, internal dynamics, and function in proteins are intimately associated. Studies of dynamics of water molecules at surface of a C-phycocyanin protein are presented.

  6. Extremely Low Frequency (ELF) Communications System Ecological Monitoring Program: Summary of 1983 progress

    NASA Astrophysics Data System (ADS)

    Zapotosky, J.; Abromovage, M. M.; Enk, J. O.

    1984-07-01

    A long-term program for studying possible effects from operation of the Navy's ELF Communication System is being conducted on biota and ecosystems components in northwestern Wisconsin and the Upper Peninsula of Michigan. Sixteen general types of organisms from three major ecosystems in the ELF System are being examined. Formulation of an ELF Ecological Monitoring Program was completed in early 1982 by the Department of the Navy. Monitoring studies were selected through a peer-reviewed, competitive bidding process in mid-1982 and studies were initiated in the late summer. Major activities of the program during 1983 consisted of characterization of critical aspects of each study, collection of data to validate assumptions made in proposals, and selection of study sites. Progress is summarized for the 10 projects that comprise the Program.

  7. System-level line-edge roughness limits in extreme ultraviolet lithography

    SciTech Connect

    Jones, Juanita; Naulleau, Patrick P; Niakoula, Dimitra; Zhang, Guojing

    2008-02-13

    As critical dimensions shrink, line edge and width roughness (LER and LWR) become of increasing concern. Traditionally LER is viewed as a resist-limited effect; however, as critical dimensions shrink and LER requirements become proportionally more stringent, system-level effects begin to play an important role. Recent advanced EUV resist testing results have demonstrated lower bounds on achievable LER at the level of approximately 2 to 3 nm. Here we use modeling to demonstrate that a significant portion of this low bound may in fact be do to system-level effects and in particular the mask. Of concern are both LER on the mask as well as roughness of the multilayer reflector. Modeling also shows roughness (flare) in the projection optics not to be of concern.

  8. ELF (Extremely Low Frequency) Communications System Ecological Monitoring Program: Summary of 1987 Progress

    DTIC Science & Technology

    1989-04-01

    of ruffed grouse, eagle, and deer populations were performed annually commencing in 1974, 1975, and 1982, respectively, and continued through 1986...There were no effects to these populations from the operation of the ELF Communications System, and the studies were concluded after the 1986 surveys...organisms, populations , communities, and ecosystems. Our current state of understanding does not allow an accurate prediction of ecological effects

  9. A Collaborative Research System for Functional Outcomes Following Wartime Extremity Vascular Injury

    DTIC Science & Technology

    2012-01-01

    Forces Health Longitudinal Technology Application. Pertinent perioperative details are entered in the GWOT-VII database (Table 2, Oracle). Within...or position of the US Air Force , US Army, US Navy, US Department of Defense, or the US Government. This work was presented at the Advanced Technology...If Defense Enrollment Eligi- bility Reporting System contact information is incorrect, commercial search engines and online armed forces e-mail

  10. Oort Cloud Asteroids: From one extreme of the Solar System to the other

    NASA Astrophysics Data System (ADS)

    Shannon, Andrew Brian; Jackson, Alan P.; Veras, Dimitri; Wyatt, Mark

    2015-12-01

    The record of planetary migration is written in the dynamics of the small bodies they leave in their wake. One such case is the production of the Oort cloud, where scattering by planets injected planetesimals into this long-lived population, which today retains a record of where and when the scattering occured. We use N-body simulations to show that for a static, collisionless solar system history, ~4% of the Oort cloud objects should have formed within 2.5 au of the Sun, and hence be ice-free rock-iron bodies. If we assume that these Oort cloud asteroids have the same size distribution as their cometary counterparts, the Large Synoptic Survey Telescope should find roughly a dozen Oort cloud asteroids during 10 years of operations. Collisional evolution can substantially change this fraction from the static case, reducing the asteroid fraction of the Oort cloud by as much as two orders of magnitude. We perform additional simulations of Solar system histories with significant planet migration, modelled on the `Nice Model' and `Grand Tack' scenarios, and find they can produce very different asteroid fractions in the Oort cloud population, thus retaining a record of the Solar system's dynamical history in the present day small body populations.

  11. The ichthyofauna of limnic systems in Quaternary deposits of extreme southern Brazil

    PubMed Central

    Assumpção, Cindy M.; Quintela, Fernando M.; Corrêa, Fabiano; Loebmann, Daniel

    2016-01-01

    Abstract The Quaternary in the state of Rio Grande do Sul (RS), southern Brazil, is geologically represented by the coastal plain and was originated by successive events of Pleistocene-Holocene marine transgressions and the occurrence of alluvial deposits. This paper aimed to characterize the fish assemblage occurring in a swampy Quaternary area adjacent to Lagoa Pequena, a lacustrine system connected to the west margin of the Laguna dos Patos estuary. A checklist is also provided of the ichthyofauna so far recorded in limnic systems of Quaternary deposits in the state of Rio Grande do Sul. A total of 42 species was recorded, distributed in nine orders, 18 families and 31 genera. Characidae and Cichlidae were the most representative families, comprising 15 and 4 species respectively. A bibliographic revision associated to our sample data revealed the occurrence of 156 species in limnic systems inserted in RS Quaternary deposits (114 limnic, 15 marine/estuarine/limnic, ten marine/estuarine, nine estuarine/limnic and eight marine). Characiformes and Siluriformes are the most diverse orders, corroborating the Neotropical pattern. Seven species can be considered endemic to RS Quaternary deposits. PMID:28174498

  12. The ichthyofauna of limnic systems in Quaternary deposits of extreme southern Brazil.

    PubMed

    Assumpção, Cindy M; Quintela, Fernando M; Corrêa, Fabiano; Loebmann, Daniel

    2016-01-01

    The Quaternary in the state of Rio Grande do Sul (RS), southern Brazil, is geologically represented by the coastal plain and was originated by successive events of Pleistocene-Holocene marine transgressions and the occurrence of alluvial deposits. This paper aimed to characterize the fish assemblage occurring in a swampy Quaternary area adjacent to Lagoa Pequena, a lacustrine system connected to the west margin of the Laguna dos Patos estuary. A checklist is also provided of the ichthyofauna so far recorded in limnic systems of Quaternary deposits in the state of Rio Grande do Sul. A total of 42 species was recorded, distributed in nine orders, 18 families and 31 genera. Characidae and Cichlidae were the most representative families, comprising 15 and 4 species respectively. A bibliographic revision associated to our sample data revealed the occurrence of 156 species in limnic systems inserted in RS Quaternary deposits (114 limnic, 15 marine/estuarine/limnic, ten marine/estuarine, nine estuarine/limnic and eight marine). Characiformes and Siluriformes are the most diverse orders, corroborating the Neotropical pattern. Seven species can be considered endemic to RS Quaternary deposits.

  13. A Path to Operating System and Runtime Support for Extreme Scale Tools

    SciTech Connect

    Miller, Barton P; Roth, Philip; DelSignore, John

    2012-08-14

    In this project, we cast distributed resource access as operations on files in a global name space and developed a common, scalable solution for group operations on distributed processes and files. The resulting solution enables tool and middleware developers to quickly create new scalable software or easily improve the scalability of existing software. The cornerstone of the project was the design of a new programming idiom called group file operations that eliminates iterative behavior when a single process must apply the same set of file operations to a group of related files. To demonstrate our novel and scalable ideas for group file operations and global name space composition, we developed a group file system called TBON-FS that leverages a tree-based overlay network (TBON), specifically MRNet, for logarithmic communication and distributed data aggregation. We also developed proc++, a new synthetic file system co-designed for use in scalable group file operations. Over the course of the project, we evaluated the utility and performance of group file operations, global name space composition, TBON-FS, and proc++ in three case studies. The first study focused on the ease in using group file operations and TBON-FS to quickly develop several new scalable tools for distributed system administration and monitoring. The second study evaluated the integration of group file operation and TBON-FS within the Ganglia Distributed Monitoring System to improve its scalability for clusters. The final study involved the integration of group file operations, TBON-FS, and proc++ within TotalView, the widely-used parallel debugger. For this project, the work of the Oak Ridge National Laboratory (ORNL) team occurred primarily in two directions: bringing the MRNet tree-based overlay network (TBON) implementation to the Cray XT platform, and investigating techniques for predicting the performance of MRNet topologies on such systems. Rogue Wave Software (RWS), formerly Total

  14. Instrumentation on the Remote Atmospheric and Ionospheric Detection System Experiment: Extreme-ultraviolet spectrometer, photometer, and near infrared spectrometer

    SciTech Connect

    Christensen, A.B.; Kayser, D.C.; Pranke, J.B.; Straus, P.R.; Gutierrez, D.G. . Space and Environment Technology Center); Chakrabarti, S. . Center for Space Physics); McCoy, R.P.; Meier, R.R.; Wolfram, K.D.; Picone, J.M. . E.O. Hulbert Center for Space Research)

    1993-12-01

    The Remote Atmospheric and Ionospheric Detection System experiment consists of eight instruments spanning the wavelength range from the extreme ultraviolet (55 nm) to the near infrared (800 nm) oriented to view the Earth's limb from the National Oceanic and Atmospheric Administration TIROS-J spacecraft to be launched into a circular orbit in 1993. Through measurements of the natural optical emissions and scattered sunlight originating in the upper atmosphere including the mesosphere and thermosphere, state variables such as temperature, composition, density, and ion concentration of this region will be inferred. The subset of instruments fabricated or otherwise provided by the Space and Environment Technology Center (formerly Space Sciences Laboratory) at The Aerospace Corporation are described.

  15. Development of the RAIDS (Remote Atmospheric and Ionospheric Detector System) extreme-ultraviolet wedge and strip detector. Technical report

    SciTech Connect

    Kayser, D.C.; Chater, W.T.; Christensen, A.B.; Howey, C.K.; Pranke, J.B.

    1989-08-28

    In the next few years the Remote Atmospheric and Ionospheric Detector System (RAIDS) package will be flown on a TIROS spacecraft. The Extreme Ultraviolet Spectrometer (EUVS) experiment contains a position-sensitive detector based on wedge and strip anode technology. A detector design has been implemented in brazed alumina and Kovar to provide a rugged bakeable housing and anode. A stack of three 80:1 microchannel plates is operated at 3500-4100 V to achieve a gain of about 10{sup 7} power. The top MCP is to be coated with MgF for increased quantum efficiency in the range of 500-1150 A. Fabrication of the wedge and strip anode on brazed alumina has presented some challenging problems. In this report, a summary of fabrication techniques and detector performance characteristics is presented.

  16. A dynamical system analysis of the development of spontaneous lower extremity movements in newborn and young infants.

    PubMed

    Gima, Hirotaka; Ohgi, Shohei; Morita, Satoru; Karasuno, Hiroshi; Fujiwara, Takayuki; Abe, Koji

    2011-01-01

    This study's aim was to evaluate the characteristics of newborn and young infants' spontaneous lower extremity movements by using dynamical systems analysis. Participants were 8 healthy full-term newborn infants (3 boys, 5 girls, mean birth weight and gestational age were 3070.6 g and 39 weeks). A tri-axial accelerometer measured limb movement acceleration in 3-dimensional space. Movement acceleration signals were recorded during 200 s from just below the ankle when the infant was in an active alert state and lying supine (sampling rate 200 Hz). Data were analyzed linearly and nonlinearly. As a result, the optimal embedding dimension showed more than 5 at all times. Time dependent changes started at 6 or 7, and over the next four months decreased to 5 and from 6 months old, increased. The maximal Lyapnov exponent was positive for all segments. The mutual information is at its greatest range at 0 months. Between 3 and 4 months the range in results is narrowest and lowest in value. The mean coefficient of correlation for the x-axis component was negative and y-axis component changed to a positive value between 1 month old and 4 months old. Nonlinear time series analysis suggested that newborn and young infants' spontaneous lower extremity movements are characterized by a nonlinear chaotic dynamics with 5 to 7 embedding dimensions. Developmental changes of an optimal embedding dimension showed a U-shaped phenomenon. In addition, the maximal Lyapnov exponents were positive for all segments (0.79-2.99). Infants' spontaneous movement involves chaotic dynamic systems that are capable of generating voluntary skill movements.

  17. [Remote intelligent Brunnstrom assessment system for upper limb rehabilitation for post-stroke based on extreme learning machine].

    PubMed

    Wang, Yue; Yu, Lei; Fu, Jianming; Fang, Qiang

    2014-04-01

    In order to realize an individualized and specialized rehabilitation assessment of remoteness and intelligence, we set up a remote intelligent assessment system of upper limb movement function of post-stroke patients during rehabilitation. By using the remote rehabilitation training sensors and client data sampling software, we collected and uploaded the gesture data from a patient's forearm and upper arm during rehabilitation training to database of the server. Then a remote intelligent assessment system, which had been developed based on the extreme learning machine (ELM) algorithm and Brunnstrom stage assessment standard, was used to evaluate the gesture data. To evaluate the reliability of the proposed method, a group of 23 stroke patients, whose upper limb movement functions were in different recovery stages, and 4 healthy people, whose upper limb movement functions were normal, were recruited to finish the same training task. The results showed that, compared to that of the experienced rehabilitation expert who used the Brunnstrom stage standard table, the accuracy of the proposed remote Brunnstrom intelligent assessment system can reach a higher level, as 92.1%. The practical effects of surgery have proved that the proposed system could realize the intelligent assessment of upper limb movement function of post-stroke patients remotely, and it could also make the rehabilitation of the post-stroke patients at home or in a community care center possible.

  18. Extreme Performance Scalable Operating Systems Final Progress Report (July 1, 2008 - October 31, 2011)

    SciTech Connect

    Malony, Allen D; Shende, Sameer

    2011-10-31

    This is the final progress report for the FastOS (Phase 2) (FastOS-2) project with Argonne National Laboratory and the University of Oregon (UO). The project started at UO on July 1, 2008 and ran until April 30, 2010, at which time a six-month no-cost extension began. The FastOS-2 work at UO delivered excellent results in all research work areas: * scalable parallel monitoring * kernel-level performance measurement * parallel I/0 system measurement * large-scale and hybrid application performance measurement * onlne scalable performance data reduction and analysis * binary instrumentation

  19. Extremely Low Frequency (ELF) communications system ecological monitoring program: Plan and summary of 1982 progress

    NASA Astrophysics Data System (ADS)

    Zapotosky, J. E.; Abromavage, M. M.

    1983-08-01

    The purpose of the Ecological Monitoring Program is to study ecological and/or biological characteristics of selected biota in an environment that includes natural stresses and low-level ELF electromagnetic fields. Sixteen general types of organisms from three major ecosystems in the System area are being examined. Study sites were selected in 1982, and will be examined further in 1983. Statistical methods of analysis proposed by investigators are identified, and biological and ecological end-points selected for study are described. Data collection began in 1982 and will be continued in 1983 for studies of vegetation, soil animals, pollinating insects, small mammals and birds, wetlands, vegetation associations, and aquatic community relationships.

  20. Postnatal systemic inflammation and neuro-ophthalmologic dysfunctions in extremely low gestational age children.

    PubMed

    Holm, Mari; Austeng, Dordi; Fichorova, Raina N; Allred, Elizabeth N; Kuban, Karl C; O'Shea, T Michael; Dammann, Olaf; Leviton, Alan

    2017-03-01

    Compared to infants born at term, children born very preterm are at increased risk of visual dysfunctions and neonatal systemic inflammation. Here, we explore whether these two propensities are related. As part of the ELGAN study, the concentrations of 16 mediators of inflammation were measured in blood obtained on postnatal days 1, 7, 14, 21 and 28 from 1062 children born before the 28th week of gestation. Presence of visual field deficit, strabismus and/or impaired visual fixation was recorded at age two. The concentrations of each protein were divided into quartiles within gestational week categories. We calculated odds ratios with 99% confidence intervals for having each disorder comparing children with concentration in the top quartile of each protein to children whose concentration was in the lower quartiles on the corresponding day. Analyses were adjusted for gestational age and birth weight Z-score. Only one of 80 assessments (16 proteins on five different days) was significant for visual field deficit, and one for impaired fixation. No association was found between strabismus and any inflammatory mediator. None of the three neuro-ophthalmologic dysfunctions assessed at two years appears to be associated with systemic inflammation measured the first four postnatal weeks. ©2016 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

  1. High-frequency electromagnetic radiation injury to the upper extremity: local and systemic effects.

    PubMed

    Ciano, M; Burlin, J R; Pardoe, R; Mills, R L; Hentz, V R

    1981-08-01

    Industrial use of radiofrequency and microwave energy sources (nonionizing, high-frequency electromagnetic radiation) is a growing and widespread phenomenon, with projected risks of exposure to more than 20 million workers in the United States. A description of the nature of this form of electromagnetic energy is given, with emphasis on the variability of energy absorption by humans. The current state of biological research is reviewed, and a summary of the known effects of radiofrequency and microwave radiation exposure on animals and humans provided. These known effects appear to be principally thermal, similar to conventional electrical burn injuries, but with some unique systemic expression. Derangements of cardiovascular, gastrointestinal, endocrine, hematological, ophthalmological, and behavioral functions are well described in animal experimentation. Two patients are presented--one a young woman exposed to a high-density radiofrequency field in an industrial setting, leading to necrosis of the entire hand and wrist as well as to a constellation of systemic effects, and one an older woman exposed to excessive microwave radiation from a malfunctioning microwave oven, leading to chronic hand pain and paresthesias resembling median nerve entrapment at the carpus. The prevalence of potential exposure in certain industries is noted and recommendations for follow-up care of workers exposed to this form of trauma are delineated.

  2. High-frequency electromagnetic radiation injury to the upper extremity: local and systemic effects

    SciTech Connect

    Ciano, M.; Burlin, J.R.; Pardoe, R.; Mills, R.L.; Hentz, V.R.

    1981-01-01

    Industrial use of radiofrequency and microwave energy sources (nonionizing, high-frequency electromagnetic radiation) is a growing and widespread phenomenon, with projected risks of exposure to more than 20 million workers in the United States. A description of the nature of this form of electromagnetic energy is given, with emphasis on the variability of energy absorption by humans. The current state of biological research is reviewed, and a summary of the known effects of radiofrequency and microwave radiation exposure on animals and humans provided. These known effects appear to be principally thermal, similar to conventional electrical burn injuries, but with some unique systemic expression. Derangements of cardiovascular, gastrointestinal, endocrine, hematological, ophthalmological, and behavioral functions are well described in animal experimentation. Two patients are presented--one a young woman exposed to a high-density radiofrequency field in an industrial setting, leading to necrosis of the entire hand and wrist as well as to a constellation of systemic effects, and one an older woman exposed to excessive microwave radiation from a malfunctioning microwave oven, leading to chronic hand pain and paresthesias resembling median nerve entrapment at the carpus. The prevalence of potential exposure in certain industries is noted and recommendations for follow-up care of workers exposed to this form of trauma are delineated.

  3. Extreme density-driven delocalization error for a model solvated-electron system

    SciTech Connect

    Johnson, Erin R. Otero-de-la-Roza, A. Dale, Stephen G.

    2013-11-14

    Delocalization (or charge-transfer) error is one of the scarce but spectacular failures of density-functional theory. It is particularly apparent in extensively delocalized molecules, and manifests in the calculation of bandgaps, reaction barriers, and dissociation limits. Even though delocalization error is always present in the self-consistent electron density, the differences from reference densities are often quite subtle and the error tends to be driven by the exchange-correlation energy expression. In this article, we propose a model system (the Kevan model) where approximate density functionals predict dramatically different charge distributions because of delocalization error. The model system consists of an electron trapped in a water hexamer and is a finite representation of an experimentally observed class of solids: electrides. The Kevan model is of fundamental interest because it allows the estimation of charge transfer error without recourse to fractional charge calculations, but our results are also relevant in the context of the modeling of confined electrons in density-functional theory.

  4. Development of the RAIDS extreme ultraviolet wedge and strip detector. [Remote Atmospheric and Ionospheric Detector System

    NASA Technical Reports Server (NTRS)

    Kayser, D. C.; Chater, W. T.; Christensen, A. B.; Howey, C. K.; Pranke, J. B.

    1988-01-01

    In the next few years the Remote Atmospheric and Ionospheric Detector System (RAIDS) package will be flown on a Tiros spacecraft. The EUV spectrometer experiment contains a position-sensitive detector based on wedge and strip anode technology. A detector design has been implemented in brazed alumina and kovar to provide a rugged bakeable housing and anode. A stack of three 80:1 microchannel plates is operated at 3500-4100 V. to achieve a gain of about 10 to the 7th. The top MCP is to be coated with MgF for increased quantum efficiency in the range of 50-115 nm. A summary of fabrication techniques and detector performance characteristics is presented.

  5. Measurement of computed tomography dose profile with pitch variation using Gafchromic XR-QA2 and thermoluminescence dosimeter (TLD)

    NASA Astrophysics Data System (ADS)

    Purwaningsih, S.; Lubis, L. E.; Pawiro, S. A.; Soejoko, D. S.

    2016-03-01

    This research was aimed to check the patterns of dose profile on adult and pediatric head scan. We compared measurement result on dose profile along the z- axis rotation at peripheries and center phantom with a variety of pitch, i.e. 0.75, 1, 1.5 for adult and pediatric head protocol, keeping the rest of the scan parameters constant. Measurements were performed on homogeneous, cylindrical PMMA phantom with diameters of 16 and 10 cm using XR-QA2 Gafchromic film and TLD as dosimeters. The measurement result indicated a decrease in the dose about 50% and 47% for adult and pediatric head scan with the increase of pitch. For 0.75 value of pitch adult head scan, dose range for each position were (2.4 - 5.0) cGy, (3.1 - 5.3) cGy, (2.2 - 4.5) cGy, (2.8 - 5.3) cGy, and (3.3 - 5.6) cGy for position of center, 3, 6, 9 and 12 o'clock peripheral phantom position respectively. Dose profile for adult and pediatric head scan protocols has pattern curve with the maximum dose in the middle and tendency of symmetry near the edges, with different the plateau length along z- axis direction in accordance to the measurement position in the phantom.

  6. Investigation of the ionisation density dependence of the glow curve characteristics of LIF:MG,TI (TLD-100)

    PubMed Central

    Horowitz, Y. S.; Horowitz, A.; Oster, L.; Marino, S.; Datz, H.; Margaliot, M.

    2008-01-01

    The dependence of the shape of the glow curve of LiF:Mg,Ti (TLD-100) on ionisation density was investigated using irradiation with 90Sr/90Y beta rays, 60 and 250 kVp X rays, various heavy-charged particles and 0.2 and 14 MeV neutrons. Special attention is focused on the properties of high-temperature thermoluminescence; specifically, the behaviour of the high-temperature ratio (HTR) of Peaks 7 and 8 as a function of batch and annealing protocol. The correlation of Peaks 7 and 8 with average linear-energy-transfer (LET) is also investigated. The HTR of Peak 7 is found to be independent of LET for values of LET approximately >30 keV µm−1. The behaviour of the HTR of Peak 8 with LET is observed to be erratic, which suggests that applications using the HTR should separate the contributions of Peaks 7 and 8 using computerised glow curve deconvolution. The behaviour of the HTR following neutron irradiation is complex and not fully understood. The shape of composite Peak 5 is observed to be broader following high ionisation alpha particle irradiation, suggesting that the combined use of the HTR and the shape of Peak 5 could lead to improved ionisation density discrimination for particles of high LET. PMID:18667402

  7. Error quantification of abnormal extreme high waves in Operational Oceanographic System in Korea

    NASA Astrophysics Data System (ADS)

    Jeong, Sang-Hun; Kim, Jinah; Heo, Ki-Young; Park, Kwang-Soon

    2017-04-01

    In winter season, large-height swell-like waves have occurred on the East coast of Korea, causing property damages and loss of human life. It is known that those waves are generated by a local strong wind made by temperate cyclone moving to eastward in the East Sea of Korean peninsula. Because the waves are often occurred in the clear weather, in particular, the damages are to be maximized. Therefore, it is necessary to predict and forecast large-height swell-like waves to prevent and correspond to the coastal damages. In Korea, an operational oceanographic system (KOOS) has been developed by the Korea institute of ocean science and technology (KIOST) and KOOS provides daily basis 72-hours' ocean forecasts such as wind, water elevation, sea currents, water temperature, salinity, and waves which are computed from not only meteorological and hydrodynamic model (WRF, ROMS, MOM, and MOHID) but also wave models (WW-III and SWAN). In order to evaluate the model performance and guarantee a certain level of accuracy of ocean forecasts, a Skill Assessment (SA) system was established as a one of module in KOOS. It has been performed through comparison of model results with in-situ observation data and model errors have been quantified with skill scores. Statistics which are used in skill assessment are including a measure of both errors and correlations such as root-mean-square-error (RMSE), root-mean-square-error percentage (RMSE%), mean bias (MB), correlation coefficient (R), scatter index (SI), circular correlation (CC) and central frequency (CF) that is a frequency with which errors lie within acceptable error criteria. It should be utilized simultaneously not only to quantify an error but also to improve an accuracy of forecasts by providing a feedback interactively. However, in an abnormal phenomena such as high-height swell-like waves in the East coast of Korea, it requires more advanced and optimized error quantification method that allows to predict the abnormal

  8. The Evolution of Energy-Transducing Systems. Studies with an Extremely Halophilic Archaebacterium

    NASA Technical Reports Server (NTRS)

    Stan-Lotter, Helga

    1997-01-01

    The F-type ATPases are found in remarkably similar versions in the energy-transducing membranes of bacteria, chloroplasts and mitochondria (1). Thus, it is likely that they have originated early in the evolution of life, which is consistent with their function as key enzymes of cellular metabolism. The archaea (formerly called archaebacteria) are a group of microorganisms which, as shown by molecular sequencing and biochemical data, have diverged early from the main line of prokaryotic evolution (2). From studies of members of all three major groups of archaea, the halophiles, methanogens and thermoacidophiles, it emerged that they possess a membrane ATPase, which differs from the F-ATPases. The goal of this project was a comparison of the ATPase from the halophilic archaebacterium Halobacterium saccharovorum with the well-characterized F-type ATPases on the molecular level. The results were expected to allow a decision about the nature of archaebacterial ATPases, their classification as one of the known or, alternatively, novel enzyme complex, and possibly a deduction of events during the early evolution of energy-transducing systems.

  9. Extreme nuclear shapes examined via giant dipole resonance lineshapes in hot light-mass systems

    SciTech Connect

    Pandit, Deepak; Mukhopadhyay, S.; Pal, Surajit; Bhattacharya, S.; Bhattacharya, C.; Banerjee, K.; Kundu, S.; Rana, T. K.; Dey, A.; Mukherjee, G.; Ghosh, T.; Banerjee, S. R.; De, A.; Gupta, D.

    2010-06-15

    The influence of alpha clustering on nuclear reaction dynamics is investigated using the giant dipole resonance (GDR) lineshape studies in the reactions {sup 20}Ne (E{sub lab}=145,160 MeV) + {sup 12}C and {sup 20}Ne (E{sub lab}=160 MeV) + {sup 27}Al, populating {sup 32}S and {sup 47}V, respectively. The GDR lineshapes from the two systems are remarkably different from each other. Whereas, the non-alpha-like {sup 47}V undergoes Jacobi shape transition and matches exceptionally well with the theoretical GDR lineshape estimated under the framework rotating liquid drop model (RLDM) and thermal shape fluctuation model (TSFM) signifying shape equilibration, for the alpha cluster {sup 32}S an extended prolate kind of shape is observed. This unusual deformation, seen directly via gamma decay for the first time, is predicted to be due to the formation of orbiting dinuclear configuration or molecular structure of {sup 16}O + {sup 16}O in the {sup 32}S superdeformed band.

  10. EXTREME CONDITIONS IN A CLOSE ANALOG TO THE YOUNG SOLAR SYSTEM: HERSCHEL OBSERVATIONS OF ε ERIDANI

    SciTech Connect

    Greaves, J. S.; Sibthorpe, B.; Holland, W. S.; Acke, B.; Vandenbussche, B.; Blommaert, J. A. D. L.; Pantin, E. E.; Dominik, C.; Barlow, M. J.; Bendo, G. J.; Dent, W. R. F.; Di Francesco, J.; Fridlund, M.; Gear, W. K.; Harvey, P. M.; Hogerheijde, M. R.; Ivison, R. J.; and others

    2014-08-10

    Far-infrared Herschel images of the ε Eridani system, seen at a fifth of the Sun's present age, resolve two belts of debris emission. Fits to the 160 μm PACS image yield radial spans for these belts of 12-16 and 54-68 AU. The south end of the outer belt is ≈10% brighter than the north end in the PACS+SPIRE images at 160, 250, and 350 μm, indicating a pericenter glow attributable to a planet ''c''. From this asymmetry and an upper bound on the offset of the belt center, this second planet should be mildly eccentric (e{sub c} ≈ 0.03-0.3). Compared to the asteroid and Kuiper Belts of the young Sun, the ε Eri belts are intermediate in brightness and more similar to each other, with up to 20 km sized collisional fragments in the inner belt totaling ≈5% of an Earth mass. This reservoir may feed the hot dust close to the star and could send many impactors through the Habitable Zone, especially if it is being perturbed by the suspected planet ε Eri b, at semi-major axis ≈3 AU.

  11. Extremely conserved ATP- or ADP-dependent enzymatic system for nicotinamide nucleotide repair.

    PubMed

    Marbaix, Alexandre Y; Noël, Gaëtane; Detroux, Aline M; Vertommen, Didier; Van Schaftingen, Emile; Linster, Carole L

    2011-12-02

    The reduced forms of NAD and NADP, two major nucleotides playing a central role in metabolism, are continuously damaged by enzymatic or heat-dependent hydration. We report the molecular identification of the eukaryotic dehydratase that repairs these nucleotides and show that this enzyme (Carkd in mammals, YKL151C in yeast) catalyzes the dehydration of the S form of NADHX and NADPHX, at the expense of ATP, which is converted to ADP. Surprisingly, the Escherichia coli homolog, YjeF, a bidomain protein, catalyzes a similar reaction, but using ADP instead of ATP. The latter reaction is ascribable to the C-terminal domain of YjeF. This represents an unprecedented example of orthologous enzymes using either ADP or ATP as phosphoryl donor. We also show that eukaryotic proteins homologous to the N-terminal domain of YjeF (apolipoprotein A-1-binding protein (AIBP) in mammals, YNL200C in yeast) catalyze the epimerization of the S and R forms of NAD(P)HX, thereby allowing, in conjunction with the energy-dependent dehydratase, the repair of both epimers of NAD(P)HX. Both enzymes are very widespread in eukaryotes, prokaryotes, and archaea, which together with the ADP dependence of the dehydratase in some species indicates the ancient origin of this repair system.

  12. The evolution of energy-transducing systems. Studies with an extremely halophilic archaebacterium

    NASA Technical Reports Server (NTRS)

    Stan-Lotter, Helga

    1992-01-01

    The F-type ATPases are found in remarkably similar versions in the energy-transducing membranes of eubacteria, chloroplasts, and mitochondria. Thus, it is likely that they have originated early in the evolution of life, which is consistent with their function as key enzymes of cellular metabolism. The archaebacteria are a group of microorganisms which, as shown by molecular sequencing and biochemical data, have diverged early from the main line of prokaryotic evolution. From studies of members of all three major groups of archaebacteria - the halophiles, methanogens, and thermoacidophiles - it emerged that they possess a membrane ATPase which differs from the F-ATPases. The goal of this project was a comparison of the ATPase from the halophilic archaebacterium Halobacterium saccharovorum with the well-characterized F-type ATPases on the molecular level. Amino acid sequences of critical regions of the enzyme were to be determined, as well as immunoreactions of single subunits in the search for common epitopes. The results were expected to allow a decision about the nature of archaebacterial ATPases, their classification as one of the known or, alternatively, novel enzyme complexes, and possibly deduction of events during the early evolution of energy-transducing systems.

  13. Design of a perfect balance system for active upper-extremity exoskeletons.

    PubMed

    Smith, Richard L; Lobo-Prat, Joan; van der Kooij, Herman; Stienen, Arno H A

    2013-06-01

    Passive gravity compensation in exoskeletons significantly reduces the amount of torque and energy needed from the actuators. So far, no design has been able to achieve perfect balance without compromising the exoskeleton characteristics. Here we propose a novel design that integrates an existing statically-balanced mechanism with two springs and four degrees of freedom into a general-purpose exoskeleton design, that can support any percentage of the combined weight of exoskeleton and arm. As it allows for three rotational degrees of freedom at the shoulder and one at the elbow, it does not compromise exoskeleton characteristics and can be powered with any choice of passive or active actuation method. For instance, with this design a perfectly balanced exoskeleton design with inherently safe, passive actuators on each joint axis becomes possible. The potential reduction in required actuator torque, power and weight, simplification of control, improved dynamic performance, and increased safety margin, all while maintaining perfect balance, are the major advantages of the design, but the integrated systems does add a significant amount of complexity. Future integration in an actual exoskeleton should prove if this tradeoff is beneficial.

  14. Significant progression of load on the musculoskeletal system with extremely high loads, with rapid weekly weight gains, using the Anatoly Gravitational System, in a 10-week training period.

    PubMed

    Burke, David T; Tran, David; Cui, Di; Burke, Daniel P; Al-Adawi, Samir; Dorvlo, Atsu Ss

    2013-01-01

    In an age of increasing numbers of lifestyle diseases and plasticity of longevity, exercise and weight training have been increasingly recognized as both preventing and mitigating the severity of many illnesses. This study was designed to determine whether significant weight-lifting gains could be realized through the Anatoly Gravitational System. Specifically, this study sought to determine whether this once-weekly weight-training system could result in significant weekly strength gains during a 10-week training period. A total of 50 participants, ranging in age from 17 to 67 years, completed at least 10 weekly 30-minute training sessions. The results suggest participants could, on average, double their weight-lifting capacity within 10 sessions. This preliminary study, which would require further scrutiny, suggests the Anatoly Gravitational System provides a rather unique opportunity to load the musculoskeletal system with extremely high loads, with rapid weekly weight gains, using only short weekly training sessions. More studies are warranted to scrutinize these findings.

  15. SU-F-19A-06: Experimental Investigation of the Energy Dependence of TLD Sensitivity in Low-Energy Photon Beams

    SciTech Connect

    Chen, Z; Nath, R

    2014-06-15

    Purpose: To measure the energy dependence of TLD sensitivity in lowenergy photon beams with equivalent mono-energetic energy matching those of 103Pd, 125I and 131Cs brachytherapy sources. Methods: A Pantek DXT 300 x-ray unit (Precision X-ray, Branford, CT), with stable digital voltage control down to 20 kV, was used to establish three lowenergy photon beams with narrow energy spread and equivalent monoenergetic energies matching those of 103Pd, 125I and 131Cs brachytherapy sources. The low-energy x-ray beams and a reference 6 MV photon beam were calibrated according to the AAPM TG-61 and TG-51 protocols, respectively, using a parallel-plate low-energy chamber and a Farmer cylindrical chamber with NIST traceable calibration factors. The dose response of model TLD-100 micro-cubes (1×1×1 mm{sup 3}) in each beam was measured for five different batches of TLDs (each contained approximately 100 TLDs) that have different histories of irradiation and usage. Relative absorbed dose sensitivity was determined as the quotient of the slope of dose response for a beam-of-interest to that of the reference beam. Results: Equivalent mono-energetic photon energies of the low-energy beams established for 103Pd, 125I and 131Cs sources were 20.5, 27.5, and 30.1 keV, respectively. Each beam exhibited narrow spectral spread with energyhomogeneity index close to 90%. The relative absorbed-dose sensitivity was found to vary between different batches of TLD with maximum differences of up to 8%. The mean and standard deviation determined from the five TLD batches was 1.453 ± 0.026, 1.541 ± 0.035 and 1.529 ± 0.051 for the simulated 103P, 125I and 131Cs beams, respectively. Conclusion: Our measured relative absorbed-dose sensitivities are greater than the historically measured value of 1.41. We find that the relative absorbed-dose sensitivity of TLD in the 103P beam is approximately 5% lower than that of 125I and 131Cs beams. Comparison of our results with other studies will be presented.

  16. The extremely populated globular cluster system of the lenticular galaxy NGC 6861

    NASA Astrophysics Data System (ADS)

    Escudero, Carlos G.; Faifer, Favio R.; Bassino, Lilia P.; Calderón, Juan Pablo; Caso, Juan Pablo

    2015-05-01

    We present a photometric study of the globular cluster (GC) system associated with the lenticular galaxy (S0) NGC 6861, which is located in a relatively low density environment. It is based on Gemini/GMOS images in the filters g', r', i' of three fields, obtained under good seeing conditions. Analysing the colour-magnitude and colour-colour diagrams, we find a large number of GC candidates, which extend out to 100 kpc, and we estimate a total population of 3000 ± 300 GCs. Besides the well-known blue and red subpopulations, the colour distribution shows signs of the possible existence of a third subpopulation with intermediate colours. This could be interpreted as evidence of a past interaction or fusion event. Other signs of interactions presented by the galaxy are the non-concentric isophotes and the asymmetric spatial distribution of GC candidates with colours (g' - i')0 > 1.16. As observed in other galaxies, the red GCs show a steeper radial distribution than the blue GCs. In addition, the spatial distribution of these candidates exhibits strong signs of elongation. This feature is also detected in the intermediate subpopulation. On the other hand, the blue candidates show an excellent agreement with the X-ray surface brightness profile, outside 10 kpc. They also show a colour-luminosity relation (blue tilt), similar to that observed in other galaxies. A new distance modulus has been estimated through the blue subpopulation, which is in good agreement with the previous value obtained through the surface brightness fluctuation method. The specific frequency of NGC 6861 (S N = 10.6 ± 2.1) is probably one of the highest values obtained for an S0 galaxy so far.

  17. Upper-Extremity and Mobility Subdomains From the Patient-Reported Outcomes Measurement Information System (PROMIS) Adult Physical Functioning Item Bank

    PubMed Central

    Hays, Ron D.; Spritzer, Karen L.; Amtmann, Dagmar; Lai, Jin-Shei; DeWitt, Esi Morgan; Rothrock, Nan; DeWalt, Darren A.; Riley, William T.; Fries, James F.; Krishnan, Eswar

    2013-01-01

    Objective To create upper-extremity and mobility subdomain scores from the Patient-Reported Outcomes Measurement Information System (PROMIS) physical functioning adult item bank. Design Expert reviews were used to identify upper-extremity and mobility items from the PROMIS item bank. Psychometric analyses were conducted to assess empirical support for scoring upper-extremity and mobility subdomains. Setting Data were collected from the U.S. general population and multiple disease groups via self-administered surveys. Participants The sample (N=21,773) included 21,133 English-speaking adults who participated in the PROMIS wave 1 data collection and 640 Spanish-speaking Latino adults recruited separately. Interventions Not applicable. Main Outcome Measures We used English- and Spanish-language data and existing PROMIS item parameters for the physical functioning item bank to estimate upper-extremity and mobility scores. In addition, we fit graded response models to calibrate the upper-extremity items and mobility items separately, compare separate to combined calibrations, and produce subdomain scores. Results After eliminating items because of local dependency, 16 items remained to assess upper extremity and 17 items to assess mobility. The estimated correlation between upper extremity and mobility was .59 using existing PROMIS physical functioning item parameters (r=.60 using parameters calibrated separately for upper-extremity and mobility items). Conclusions Upper-extremity and mobility subdomains shared about 35% of the variance in common, and produced comparable scores whether calibrated separately or together. The identification of the subset of items tapping these 2 aspects of physical functioning and scored using the existing PROMIS parameters provides the option of scoring these subdomains in addition to the overall physical functioning score. PMID:23751290

  18. The Use of TLD and Gafchromic Film to Assure Submillimeter Accuracy for Image-Guided Radiosurgery

    SciTech Connect

    Ho, Anthony K. Gibbs, Iris C.; Chang, Steve D.; Main, Bill; Adler, John R.

    2008-04-01

    The Cyberknife is an image-guided radiosurgical system. It uses a compact X-band 6-MV linear accelerator mounted on a robotic arm to deliver radiosurgical doses. While routine quality assurance (QA) is essential for any radiosurgery system, QA plays an even more vital role for the Cyberknife system, due to the complexity of the system and the wide range of applications. This paper presents a technique for performing quality assurance using thermoluminescence detectors (TLDs) and Gafchromic films that is intended to be specific for the Cyberknife. However, with minor modification, the proposed method can also be used for QA of other radiosurgery systems. Our initial QA procedure for the CyberKnife utilized a 30 x 30 x 11-cm solid water phantom containing a planar array of slots for 1x 1 x 1-mm TLDs on a 2-mm grid. With the objective of significantly simplifying CyberKnife QA, a new procedure for verification was developed, which uses much fewer TLDs than the prior solid water phantom technique. This new method requires only that the system target dose to the center of a cluster of 7 TLDs. In a prior study with Gafchromic films, conducted at 3 different Cyberknife facilities, the mean clinically relevant error was demonstrated to be 0.7 mm. A similar Gafchromic film analysis replicated these error measurements as part of the present investigation. It cannot be emphasized enough the importance of implementing routine QA to verify the accuracy of any radiosurgery system. Our quality assurance procedure tests the treatment planning system, as well as the entire treatment delivery including the image targeting system and the robot system. Either TLDs or Gafchromic films may be used for QA test of a radiosurgery system. Using both methods for measurement has the advantage independently verifying the accuracy of the system. This approach, which is routinely in used at our institution, has repeatedly confirmed the submillimeter targeting accuracy of our Cyberknife.

  19. Evidence for a distant unseen solar system planet: Assessing the observational biases in the extreme Kuiper belt population

    NASA Astrophysics Data System (ADS)

    Volk, Kathryn; Malhotra, Renu

    2016-10-01

    Several recent studies have appealed to peculiarities in the observed distribution of very distant, extreme Kuiper belt objects (eKBOs) to argue for the existence of an Earth-mass or larger planet in the distant solar system. Trujillo and Sheppard (2014) noted that the arguments of perihelion of the observed eKBOs cluster near 0, and Batygin & Brown (2016) noted that the eKBOs also have clustered orbit poles and eccentricity vectors (which result in clustered longitudes of perihelion and longitudes of ascending node). Both papers argue that observational biases are unlikely to explain the observed clustering. Because the observed population of eKBOs is far from complete, a thorough assessment of the observational biases in the population is warranted. Very accurate assessment of observational biases is only possible for objects discovered by well-characterized surveys, but the number of eKBOs found by such surveys is small. We instead use the set of observed KBOs in the Minor Planet Center catalog along with published survey pointings and limiting magnitudes to approximately reconstruct the biases in the observed eKBO population. We will report on the role of observational biases in either strengthening or weakening the case for a distant unseen planet in our solar system. This research was supported by NASA (grant NNX14AG93G).

  20. Structural and functional responses of extremity veins to long-term gravitational loading or unloading—lessons from animal systems

    NASA Astrophysics Data System (ADS)

    Monos, Emil; Raffai, Gábor; Dörnyei, Gabriella; Nádasy, György L.; Fehér, Erzsébet

    2007-02-01

    Long, transparent tubular tilt-cages were developed to maintain experimental rats either in 45∘ head-up (orthostasis model), or in 45∘ head-down body position (antiorthostasis model) for several weeks. In order to study the functional and structural changes in extremity blood vessels, also novel pressure angiograph systems, as well as special quantitative electron microscopic methods were applied. It was found that several adaptive mechanisms are activated in the lower limb superficial veins and microvessels of muscles when an organism is exposed to long-term (1-2 weeks) orthostatic-type gravitational load including a reversible amplification of the pressure-dependent myogenic response, tuning of the myogenic tone by Ca++- and voltage-sensitive K+ channels in humans, augmentation of the intramural sympathetic innervation involving an increased nerve terminal density and synaptic vesicle count with functional remodeling, reorganization of vascular network properties (microvascular rarefaction in muscles, decreased branching angles in superficial veins), and responses of an endothelin and platelet-derived growth factor (PDGF) containing vesicle system in the endothelium. On the other hand, when applying long-term head-down tilting, the effects are dichotomous, e.g. it suppresses significantly the pressure-induced myogenic response, however does not diminish the adventitial sympathetic innervation density.

  1. Improving Global Forecast System of extreme precipitation events with regional statistical model: Application of quantile-based probabilistic forecasts

    NASA Astrophysics Data System (ADS)

    Shastri, Hiteshri; Ghosh, Subimal; Karmakar, Subhankar

    2017-02-01

    Forecasting of extreme precipitation events at a regional scale is of high importance due to their severe impacts on society. The impacts are stronger in urban regions due to high flood potential as well high population density leading to high vulnerability. Although significant scientific improvements took place in the global models for weather forecasting, they are still not adequate at a regional scale (e.g., for an urban region) with high false alarms and low detection. There has been a need to improve the weather forecast skill at a local scale with probabilistic outcome. Here we develop a methodology with quantile regression, where the reliably simulated variables from Global Forecast System are used as predictors and different quantiles of rainfall are generated corresponding to that set of predictors. We apply this method to a flood-prone coastal city of India, Mumbai, which has experienced severe floods in recent years. We find significant improvements in the forecast with high detection and skill scores. We apply the methodology to 10 ensemble members of Global Ensemble Forecast System and find a reduction in ensemble uncertainty of precipitation across realizations with respect to that of original precipitation forecasts. We validate our model for the monsoon season of 2006 and 2007, which are independent of the training/calibration data set used in the study. We find promising results and emphasize to implement such data-driven methods for a better probabilistic forecast at an urban scale primarily for an early flood warning.

  2. APE: the Active Phasing Experiment to test new control system and phasing technology for a European Extremely Large Optical Telescope

    NASA Astrophysics Data System (ADS)

    Gonte, F.; Yaitskova, N.; Derie, F.; Constanza, A.; Brast, R.; Buzzoni, B.; Delabre, B.; Dierickx, P.; Dupuy, C.; Esteves, R.; Frank, C.; Guisard, S.; Karban, R.; Koenig, E.; Kolb, J.; Nylund, M.; Noethe, L.; Surdej, I.; Courteville, A.; Wilhelm, R.; Montoya, L.; Reyes, M.; Esposito, S.; Pinna, E.; Dohlen, K.; Ferrari, M.; Langlois, M.

    2005-08-01

    The future European Extremely Large Telescope will be composed of one or two giant segmented mirrors (up to 100 m of diameter) and of several large monolithic mirrors (up to 8 m in diameter). To limit the aberrations due to misalignments and defective surface quality it is necessary to have a proper active optics system. This active optics system must include a phasing system to limit the degradation of the PSF due to misphasing of the segmented mirrors. We will present the lastest design and development of the Active Phasing Experiment that will be tested in laboratory and on-sky connected to a VLT at Paranal in Chile. It includes an active segmented mirror, a static piston plate to simulate a secondary segmented mirror and of four phasing wavefront sensors to measure the piston, tip and tilt of the segments and the aberrations of the VLT. The four phasing sensors are the Diffraction Image Phase Sensing Instrument developed by Instituto de Astrofisica de Canarias, the Pyramid Phasing Sensor developed by Arcetri Astrophysical Observatory, the Shack-Hartmann Phasing Sensor developed by the European Southern Observatory and the Zernike Unit for Segment phasing developed by Laboratoire d'Astrophysique de Marseille. A reference measurement of the segmented mirror is made by an internal metrology developed by Fogale Nanotech. The control system of Active Phasing Experiment will perform the phasing of the segments, the guiding of the VLT and the active optics of the VLT. These activities are included in the Framework Programme 6 of the European Union.

  3. Efficiently feeding single-mode fiber photonic spectrographs with an extreme adaptive optics system: on-sky characterization and preliminary spectroscopy

    NASA Astrophysics Data System (ADS)

    Jovanovic, N.; Cvetojevic, N.; Schwab, C.; Norris, B.; Lozi, J.; Gross, S.; Betters, C.; Singh, G.; Guyon, O.; Martinache, F.; Doughty, D.; Tuthill, P.

    2016-08-01

    High-order wavefront correction is not only beneficial for high-contrast imaging, but also spectroscopy. The size of a spectrograph can be decoupled from the size of the telescope aperture by moving to the diffraction limit which has strong implications for ELT based instrument design. Here we present the construction and characterization of an extremely efficient single-mode fiber feed behind an extreme adaptive optics system (SCExAO). We show that this feed can indeed be utilized to great success by photonic-based spectrographs. We present metrics to quantify the system performance and some preliminary spectra delivered by the compact spectrograph.

  4. Using long term synthetic time series to assess the impact of meteorological extreme events on renewable energy systems: a case study of wind and hydro power in Sweden

    NASA Astrophysics Data System (ADS)

    Höltinger, Stefan; Schmidt, Johannes; Weterlund, Elisabeth

    2017-04-01

    Synthetic time series of renewable energy generation provide important inputs for energy system models that study the transition to low carbon energy systems. The coverage of national energy statistics is usually too short or temporal resolution too low - in particular if meteorological extreme events should be assessed. These extreme events may put high stress on power systems with very high shares of renewables and therefore have to be studied in detail. We use simulated time series of Swedish wind energy generation for a 35 year period based on MERRA reanalysis datasets. The simulation of hydropower generation is more complex and requires hydrological models that combine precipitation data with spatially explicit information on soil type and land cover to simulate river discharge. For this purpose, we use time series of daily river discharge that have been simulated using the open source model HYPE (HYdrological Predictions for the Environment). We compared the derived time series for wind and hydropower generation in the four Swedish bidding areas with respect to their long-term correlation, patterns of seasonality, and length and duration of extreme events. Preliminary results show that expanding wind power capacities could significantly reduce the overall variability of renewable energy generation. Furthermore, the frequency and duration of extreme production events in a combined wind-hydropower system is lower than in a hydropower system only. Further work will study the need for backup capacities in a future Swedish power system with very high shares of hydro, wind and solar power (>90%).

  5. Extreme Programming: Maestro Style

    NASA Technical Reports Server (NTRS)

    Norris, Jeffrey; Fox, Jason; Rabe, Kenneth; Shu, I-Hsiang; Powell, Mark

    2009-01-01

    "Extreme Programming: Maestro Style" is the name of a computer programming methodology that has evolved as a custom version of a methodology, called extreme programming that has been practiced in the software industry since the late 1990s. The name of this version reflects its origin in the work of the Maestro team at NASA's Jet Propulsion Laboratory that develops software for Mars exploration missions. Extreme programming is oriented toward agile development of software resting on values of simplicity, communication, testing, and aggressiveness. Extreme programming involves use of methods of rapidly building and disseminating institutional knowledge among members of a computer-programming team to give all the members a shared view that matches the view of the customers for whom the software system is to be developed. Extreme programming includes frequent planning by programmers in collaboration with customers, continually examining and rewriting code in striving for the simplest workable software designs, a system metaphor (basically, an abstraction of the system that provides easy-to-remember software-naming conventions and insight into the architecture of the system), programmers working in pairs, adherence to a set of coding standards, collaboration of customers and programmers, frequent verbal communication, frequent releases of software in small increments of development, repeated testing of the developmental software by both programmers and customers, and continuous interaction between the team and the customers. The environment in which the Maestro team works requires the team to quickly adapt to changing needs of its customers. In addition, the team cannot afford to accept unnecessary development risk. Extreme programming enables the Maestro team to remain agile and provide high-quality software and service to its customers. However, several factors in the Maestro environment have made it necessary to modify some of the conventional extreme

  6. The use of lower tourniquet inflation pressures in extremity surgery facilitated by curved and wide tourniquets and an integrated cuff inflation system.

    PubMed

    Pedowitz, R A; Gershuni, D H; Botte, M J; Kuiper, S; Rydevik, B L; Hargens, A R

    1993-02-01

    Use of the lowest possible cuff inflation pressure should minimize the pathogenic effects of compression beneath the pneumatic tourniquet. Curved tourniquets (designed to fit conically shaped limbs) and wider tourniquets were associated with significantly lower arterial occlusion pressure (AOP) than standard, straight tourniquets on the arms and legs of 26 normal volunteers. These tourniquets were used with an integrated tourniquet inflation system in 29 upper-extremity and 31 lower-extremity surgeries. Mean tourniquet inflation pressures of 183.7 mm Hg and 208 mm Hg were used during various surgical procedures of the arm and leg, respectively. Incomplete hemostasis was associated with elevated systolic blood pressure in several cases, but acceptable surgical hemostasis was achieved by incremental increase of the cuff inflation pressure. Curved cuffs, wide cuffs, and an integrated cuff inflation system should facilitate the use of lower tourniquet inflation pressures in extremity surgery.

  7. Extreme Precipitation and Emergency Room Visits for Gastrointestinal Illness in Areas with and without Combined Sewer Systems: An Analysis of Massachusetts Data, 2003–2007

    PubMed Central

    Li, Quanlin; Wang, Shiliang; Messier, Kyle P.; Wade, Timothy J.; Hilborn, Elizabeth D.

    2015-01-01

    Background Combined sewer overflows (CSOs) occur in combined sewer systems when sewage and stormwater runoff are released into water bodies, potentially contaminating water sources. CSOs are often caused by heavy precipitation and are expected to increase with increasing extreme precipitation associated with climate change. Objectives The aim of this study was to assess whether the association between heavy rainfall and rate of emergency room (ER) visits for gastrointestinal (GI) illness differed in the presence of CSOs. Methods For the study period 2003–2007, time series of daily rate of ER visits for GI illness and meteorological data were organized for three exposure regions: a) CSOs impacting drinking water sources, b) CSOs impacting recreational waters, c) no CSOs. A distributed lag Poisson regression assessed cumulative effects for an 8-day lag period following heavy (≥ 90th and ≥ 95th percentile) and extreme (≥ 99th percentile) precipitation events, controlling for temperature and long-term time trends. Results The association between extreme rainfall and rate of ER visits for GI illness differed among regions. Only the region with drinking water exposed to CSOs demonstrated a significant increased cumulative risk for rate (CRR) of ER visits for GI for all ages in the 8-day period following extreme rainfall: CRR: 1.13 (95% CI: 1.00, 1.28) compared with no rainfall. Conclusions The rate of ER visits for GI illness was associated with extreme precipitation in the area with CSO discharges to a drinking water source. Our findings suggest an increased risk for GI illness among consumers whose drinking water source may be impacted by CSOs after extreme precipitation. Citation Jagai JS, Li Q, Wang S, Messier KP, Wade TJ, Hilborn ED. 2015. Extreme precipitation and emergency room visits for gastrointestinal illness in areas with and without combined sewer systems: an analysis of Massachusetts data, 2003–2007. Environ Health Perspect 123:873–879;

  8. Extreme Precipitation and Emergency Room Visits for Gastrointestinal Illness in Areas with and without Combined Sewer Systems: An Analysis of Massachusetts Data, 2003-2007.

    PubMed

    Jagai, Jyotsna S; Li, Quanlin; Wang, Shiliang; Messier, Kyle P; Wade, Timothy J; Hilborn, Elizabeth D

    2015-09-01

    Combined sewer overflows (CSOs) occur in combined sewer systems when sewage and stormwater runoff are released into water bodies, potentially contaminating water sources. CSOs are often caused by heavy precipitation and are expected to increase with increasing extreme precipitation associated with climate change. The aim of this study was to assess whether the association between heavy rainfall and rate of emergency room (ER) visits for gastrointestinal (GI) illness differed in the presence of CSOs. For the study period 2003-2007, time series of daily rate of ER visits for GI illness and meteorological data were organized for three exposure regions: a) CSOs impacting drinking water sources, b) CSOs impacting recreational waters, c) no CSOs. A distributed lag Poisson regression assessed cumulative effects for an 8-day lag period following heavy (≥ 90th and ≥ 95th percentile) and extreme (≥ 99th percentile) precipitation events, controlling for temperature and long-term time trends. The association between extreme rainfall and rate of ER visits for GI illness differed among regions. Only the region with drinking water exposed to CSOs demonstrated a significant increased cumulative risk for rate (CRR) of ER visits for GI for all ages in the 8-day period following extreme rainfall: CRR: 1.13 (95% CI: 1.00, 1.28) compared with no rainfall. The rate of ER visits for GI illness was associated with extreme precipitation in the area with CSO discharges to a drinking water source. Our findings suggest an increased risk for GI illness among consumers whose drinking water source may be impacted by CSOs after extreme precipitation. Jagai JS, Li Q, Wang S, Messier KP, Wade TJ, Hilborn ED. 2015. Extreme precipitation and emergency room visits for gastrointestinal illness in areas with and without combined sewer systems: an analysis of Massachusetts data, 2003-2007. Environ Health Perspect 123:873-879; http://dx.doi.org/10.1289/ehp.1408971.

  9. Ocean Dynamics Simulation during an Extreme Bora Event using a Two-Way Coupled Atmosphere-Ocean Modeling System

    NASA Astrophysics Data System (ADS)

    Licer, Matjaz; Smerkol, Peter; Fettich, Anja; Ravdas, Michalis; Papapostolou, Alexandros; Mantziafou, Anneta; Cedilnik, Jure; Strajnar, Benedikt; Jeromel, Maja; Pristov, Neva; Jerman, Jure; Petan, Saso; Malacic, Vlado; Sofianos, Sarantis

    2015-04-01

    The response of the Adriatic Sea to cold north-easterly Bora wind forcing has been modelled numerous times, but usually using one-way coupling techniques. One of the most significant events of the kind took place in February 2012, when hurricane force Bora was blowing over the Northern Adriatic almost continuously for over three weeks, causing extreme air-sea interactions leading to severe water cooling (below 4 degrees Celsius) and extensive dense water formation (with density anomalies above 30.5 kg/m3). The intensity of the atmosphere-ocean interactions during such conditions calls for a two-way atmosphere-ocean coupling approach. We compare the performances of a) fully two-way coupled atmosphere-ocean modelling system and b) one way coupled ocean model (forced by the atmospheric model hourly output) to the available in-situ measurements (coastal buoy, CTD). The models used were ALADIN (4.4 km resolution) on the atmospheric side and POM (1/30°× 1/30° resolution) on the ocean side. The atmosphere-ocean coupling was implemented using the OASIS3-MCT model coupling toolkit. We show that the atmosphere-ocean two-way coupling significantly improves the simulated temperature and density response of the ocean since it represents short-termed transient features much better than the offline version of the ocean model.

  10. HIGH FILL-OUT, EXTREME MASS RATIO OVERCONTACT BINARY SYSTEMS. X. THE NEWLY DISCOVERED BINARY XY LEONIS MINORIS

    SciTech Connect

    Qian, S.-B.; Liu, L.; Zhu, L.-Y.; He, J.-J.; Bernasconi, L. E-mail: yygcn@163.com

    2011-05-15

    The newly discovered short-period close binary star, XY LMi, has been monitored photometrically since 2006. Its light curves are typical EW-type light curves and show complete eclipses with durations of about 80 minutes. Photometric solutions were determined through an analysis of the complete B, V, R, and I light curves using the 2003 version of the Wilson-Devinney code. XY LMi is a high fill-out, extreme mass ratio overcontact binary system with a mass ratio of q = 0.148 and a fill-out factor of f = 74.1%, suggesting that it is in the late evolutionary stage of late-type tidal-locked binary stars. As observed in other overcontact binary stars, evidence for the presence of two dark spots on both components is given. Based on our 19 epochs of eclipse times, we found that the orbital period of the overcontact binary is decreasing continuously at a rate of dP/dt = -1.67 x 10{sup -7} days yr{sup -1}, which may be caused by mass transfer from the primary to the secondary and/or angular momentum loss via magnetic stellar wind. The decrease of the orbital period may result in the increase of the fill-out, and finally, it will evolve into a single rapid-rotation star when the fluid surface reaches the outer critical Roche lobe.

  11. Occupational exposure to intermediate frequency and extremely low frequency magnetic fields among personnel working near electronic article surveillance systems.

    PubMed

    Roivainen, Päivi; Eskelinen, Tuomo; Jokela, Kari; Juutilainen, Jukka

    2014-05-01

    Cashiers are potentially exposed to intermediate frequency (IF) magnetic fields at their workplaces because of the electronic article surveillance (EAS) systems used in stores to protect merchandise against theft. This study aimed at investigating occupational exposure of cashiers to IF magnetic fields in Finnish stores. Exposure to extremely low frequency (ELF) magnetic fields was also evaluated because cashiers work near various devices operating with 50 Hz electric power. The peak magnetic flux density was measured for IF magnetic fields, and was found to vary from 0.2 to 4 µT at the cashier's seat. ELF magnetic fields from 0.03 to 4.5 µT were found at the cashier's seat. These values are much lower than exposure limits. However, according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) occupational reference levels for IF magnetic fields (141 µT for the peak field) were exceeded in some cases (maximum 189 µT) for short periods of time when cashiers walked through the EAS gates. As the ICNIRP reference levels do not define any minimum time for exposure, additional investigations are recommended to determine compliance with basic restrictions. Even if the basic restrictions are not exceeded, persons working near EAS devices represent an exceptional group of workers with respect to exposure to electromagnetic fields. This group could serve as a basis for epidemiological studies addressing possible health effects of IF magnetic fields. Compliance with the reference levels for IF fields was evaluated using both broadband measurement of peak fields and the ICNIRP summation rule for multiple frequencies. The latter was generally more conservative, and the difference between the two methods was large (>10-fold) for EAS systems using a 58 kHz signal with complex waveform. This indicates that the ICNIRP multiple frequency rule can be unnecessarily conservative when measuring complex waveforms. © 2014 Wiley Periodicals, Inc.

  12. Portal vein and systemic adiponectin concentrations are closely linked with hepatic glucose and lipoprotein kinetics in extremely obese subjects.

    PubMed

    Magkos, Faidon; Fabbrini, Elisa; Patterson, Bruce W; Eagon, J Christopher; Klein, Samuel

    2011-11-01

    Low systemic plasma adiponectin concentrations are associated with abnormalities in hepatic glucose and lipoprotein metabolism in obese people. However, the relationship between the delivery of adiponectin to the liver via the portal vein and hepatic glucose and lipoprotein metabolism is not known. We examined the relationship between hepatic substrate metabolism (glucose rate of appearance into plasma and hepatic very low-density lipoprotein [VLDL]-triglyceride [TG] and VLDL-apolipoprotein B-100 [apoB-100] secretion rates, determined by using stable isotope-labeled tracer techniques) and portal vein adiponectin concentration, in 8 insulin-resistant, extremely obese subjects (body mass index, 65 ± 7 kg/m(2)). Portal vein adiponectin concentration was inversely associated with basal glucose rate of appearance (r = -0.820, P = .013) and VLDL-TG (r = -0.823, P = .012) and VLDL-apoB-100 (r = -0.787, P = .020) secretion rates. Very similar correlations were obtained for radial artery adiponectin as a result of a mirroring relationship between portal and arterial adiponectin concentrations (r = 0.899, P = .002) and the absence of significant arteriovenous concentration differences (P = .570). Insulin resistance, assessed with the homeostasis model assessment score, was also strongly associated with hepatic glucose and lipid metabolic parameters, as well as with adiponectin concentrations in the portal vein and radial artery. These results suggest that adiponectin delivery to the liver, whether via the portal or the systemic circulation, may be an important regulator of basal hepatic glucose, VLDL-TG, and VLDL-apoB-100 production rates in obese people, possibly through direct effects on the liver or changes in hepatic insulin sensitivity. However, portal vein adiponectin does not appear to be superior to arterial adiponectin as a marker of hepatic metabolic dysregulation. Additional studies are needed to elucidate the mechanism(s) responsible for the strong association

  13. Coherent pulse interrogation system for fiber Bragg grating sensing of strain and pressure in dynamic extremes of materials

    DOE PAGES

    Rodriguez, George; Jaime, Marcelo; Balakirev, Fedor; ...

    2015-05-21

    A 100 MHz fiber Bragg grating (FBG) interrogation system is described and applied to strain and pressure sensing. The approach relies on coherent pulse illumination of the FBG sensor with a broadband short pulse from a femtosecond modelocked erbium fiber laser. After interrogation of the FBG sensor, a long multi-kilometer run of single mode fiber is used for chromatic dispersion to temporally stretch the spectral components of the reflected pulse from the FBG sensor. Dynamic strain or pressure induced spectral shifts in the FBG sensor are detected as a pulsed time domain waveform shift after encoding by the chromatic dispersivemore » line. Signals are recorded using a single 35 GHz photodetector and a 50 GSamples per second, 25 GHz bandwidth, digitizing oscilloscope. Application of this approach to high-speed strain sensing in magnetic materials in pulsed magnetic fields to ~150 T is demonstrated. The FBG wavelength shifts are used to study magnetic field driven magnetostriction effects in LaCoO₃. A sub-microsecond temporal shift in the FBG sensor wavelength attached to the sample under first order phase change appears as a fractional length change (strain: ΔL/L<10⁻⁴) in the material. A second application used FBG sensing of pressure dynamics to nearly 2 GPa in the thermal ignition of the high explosive PBX-9501 is also demonstrated. In conclusion, both applications demonstrate the use of this FBG interrogation system in dynamical extreme conditions that would otherwise not be possible using traditional FBG interrogation approaches that are deemed too slow to resolve such events.« less

  14. Extreme genetic heterogeneity among the nine major tribal Taiwanese island populations detected with a new generation Y23 STR system.

    PubMed

    Zeng, Zhaoshu; Garcia-Bertrand, Ralph; Calderon, Silvia; Li, Li; Zhong, Mingxia; Herrera, Rene J

    2014-09-01

    The Taiwanese aborigines have been regarded as the source populations for the Austronesian expansion that populated Oceania to the east and Madagascar off Africa to the West. Although a number of genetic studies have been performed on some of these important tribes, the scope of the investigations has been limited, varying in the specific populations examined as well as the maker systems employed. This has made direct comparison among studies difficult. In an attempt to alleviate this lacuna, we investigate, for the first time, the genetic diversity of all nine major Taiwanese aboriginal tribes (Ami, Atayal, Bunun, Rukai, Paiwan, Saisat, Puyuma, Tsou and Yami) utilizing a new generation multiplex Y-STR system that allows for the genotyping of 23 loci from a single amplification reaction. This comprehensive approach examining 293 individuals from all nine main tribes with the same battery of forensic markers provides for the much-needed equivalent data essential for comparative analyses. Our results have uncovered that these nine major aboriginal populations exhibit limited intrapopulation genetic diversity and are highly heterogeneous from each other, possibly the result of endogamy, isolation, drift and/or unique ancestral populations. Specifically, genetic diversity, discrimination capacity, fraction of unique haplotypes and the most frequent haplotypes differ among the nine tribes, with the Tsou possessing the lowest values for the first three of these parameters. The phylogenetic analyses performed indicate that the genetic diversity among all nine tribes is greater than the diversity observed among the worldwide reference populations examined, indicating an extreme case of genetic heterogeneity among these tribes that have lived as close neighbors for thousands of years confined to the limited geographical area of an island. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  15. Coherent pulse interrogation system for fiber Bragg grating sensing of strain and pressure in dynamic extremes of materials

    SciTech Connect

    Rodriguez, George; Jaime, Marcelo; Balakirev, Fedor; Mielke, Chuck H.; Azad, Abul; Marshall, Bruce; La Lone, Brandon M.; Henson, Bryan; Smilowitz, Laura

    2015-05-21

    A 100 MHz fiber Bragg grating (FBG) interrogation system is described and applied to strain and pressure sensing. The approach relies on coherent pulse illumination of the FBG sensor with a broadband short pulse from a femtosecond modelocked erbium fiber laser. After interrogation of the FBG sensor, a long multi-kilometer run of single mode fiber is used for chromatic dispersion to temporally stretch the spectral components of the reflected pulse from the FBG sensor. Dynamic strain or pressure induced spectral shifts in the FBG sensor are detected as a pulsed time domain waveform shift after encoding by the chromatic dispersive line. Signals are recorded using a single 35 GHz photodetector and a 50 GSamples per second, 25 GHz bandwidth, digitizing oscilloscope. Application of this approach to high-speed strain sensing in magnetic materials in pulsed magnetic fields to ~150 T is demonstrated. The FBG wavelength shifts are used to study magnetic field driven magnetostriction effects in LaCoO₃. A sub-microsecond temporal shift in the FBG sensor wavelength attached to the sample under first order phase change appears as a fractional length change (strain: ΔL/L<10⁻⁴) in the material. A second application used FBG sensing of pressure dynamics to nearly 2 GPa in the thermal ignition of the high explosive PBX-9501 is also demonstrated. In conclusion, both applications demonstrate the use of this FBG interrogation system in dynamical extreme conditions that would otherwise not be possible using traditional FBG interrogation approaches that are deemed too slow to resolve such events.

  16. Lyot-based low order wavefront sensor: implementation on the Subaru Coronagraphic Extreme Adaptive Optics System and its laboratory performance

    NASA Astrophysics Data System (ADS)

    Singh, Garima; Guyon, Olivier; Baudoz, Pierre; Jovanovich, Nemanja; Martinache, Frantz; Kudo, Tomoyuki; Serabyn, Eugene; Kuhn, Jonas G.

    2014-08-01

    High throughput, low inner working angle (IWA) phase masks coronagraphs are essential to directly image and characterize (via spectroscopy) earth-like planets. However, the performance of low-IWA coronagraphs is limited by residual pointing errors and other low-order modes. The extent to which wavefront aberrations upstream of the coronagraph are corrected and calibrated drives coronagraphic performance. Addressing this issue is essential for preventing coronagraphic leaks, thus we have developed a Lyot-based low order wave front sensor (LLOWFS) to control the wavefront aberrations in a coronagraph. The LLOWFS monitors the starlight rejected by the coronagraphic mask using a reflective Lyot stop in the downstream pupil plane. The early implementation of LLOWFS at LESIA, Observatoire de Paris demonstrated an open loop measurement accuracy of 0.01 λ/D for tip-tilt at 638 nm when used in conjunction with a four quadrant phase mask (FQPM) in the laboratory. To further demonstrate our concept, we have installed the reflective Lyot stops on the Subaru Coronagraphic Extreme AO (SCExAO) system at the Subaru Telescope and modified the system to support small IWA phase mask coronagraphs (< 1λ/D) on-sky such as FQPM, eight octant phase mask, vector vortex coronagraph and the phase induced amplitude apodization complex phase mask coronagraph with a goal of obtaining milli arc-second pointing accuracy. Laboratory results have shown the measurement of tip, tilt, focus, oblique and right astigmatism at 1.55 μm for the vector vortex coronagraph. Our initial on-sky result demonstrate the closed loop accuracy of < 7 x 10-3 λ/D at 1.6 μm for tip, tilt and focus aberrations with the vector vortex coronagraph.

  17. Coherent pulse interrogation system for fiber Bragg grating sensing of strain and pressure in dynamic extremes of materials

    DOE PAGES

    Rodriguez, George; Jaime, Marcelo; Balakirev, Fedor; ...

    2015-05-21

    A 100 MHz fiber Bragg grating (FBG) interrogation system is described and applied to strain and pressure sensing. The approach relies on coherent pulse illumination of the FBG sensor with a broadband short pulse from a femtosecond modelocked erbium fiber laser. After interrogation of the FBG sensor, a long multi-kilometer run of single mode fiber is used for chromatic dispersion to temporally stretch the spectral components of the reflected pulse from the FBG sensor. Dynamic strain or pressure induced spectral shifts in the FBG sensor are detected as a pulsed time domain waveform shift after encoding by the chromatic dispersivemore » line. Signals are recorded using a single 35 GHz photodetector and a 50 GSamples per second, 25 GHz bandwidth, digitizing oscilloscope. Application of this approach to high-speed strain sensing in magnetic materials in pulsed magnetic fields to ~150 T is demonstrated. The FBG wavelength shifts are used to study magnetic field driven magnetostriction effects in LaCoO₃. A sub-microsecond temporal shift in the FBG sensor wavelength attached to the sample under first order phase change appears as a fractional length change (strain: ΔL/L<10⁻⁴) in the material. A second application used FBG sensing of pressure dynamics to nearly 2 GPa in the thermal ignition of the high explosive PBX-9501 is also demonstrated. In conclusion, both applications demonstrate the use of this FBG interrogation system in dynamical extreme conditions that would otherwise not be possible using traditional FBG interrogation approaches that are deemed too slow to resolve such events.« less

  18. TLD skin dose measurements and acute and late effects after lumpectomy and high-dose-rate brachytherapy only for early breast cancer

    SciTech Connect

    Perera, Francisco . E-mail: francisco.perera@lrcc.on.ca; Chisela, Frank; Stitt, Larry; Engel, Jay; Venkatesan, Varagur

    2005-08-01

    Purpose: This report examines the relationships between measured skin doses and the acute and late skin and soft tissue changes in a pilot study of lumpectomy and high-dose-rate brachytherapy only for breast cancer. Methods and Materials: Thirty-seven of 39 women enrolled in this pilot study of high-dose-rate brachytherapy (37.2 Gy in 10 fractions b.i.d.) each had thermoluminescent dosimetry (TLD) at 5 points on the skin of the breast overlying the implant volume. Skin changes at TLD dose points and fibrosis at the lumpectomy site were documented every 6 to 12 months posttreatment using a standardized physician-rated cosmesis questionnaire. The relationships between TLD dose and acute skin reaction, pigmentation, or telangiectasia at 5 years were analyzed using the GEE algorithm and the GENMOD procedure in the SAS statistical package. Fisher's exact test was used to determine whether there were any significant associations between acute skin reaction and late pigmentation or telangiectasia or between the volumes encompassed by various isodoses and fibrosis or fat necrosis. Results: The median TLD dose per fraction (185 dose points) multiplied by 10 was 9.2 Gy. In all 37 patients, acute skin reaction Grade 1 or higher was observed at 5.9% (6 of 102) of dose points receiving 10 Gy or less vs. 44.6% (37 of 83) of dose points receiving more than 10 Gy (p < 0.0001). In 25 patients at 60 months, 1.5% telangiectasia was seen at dose points receiving 10 Gy or less (1 of 69) vs. 18% (10 of 56) telangiectasia at dose points receiving more than 10 Gy (p 0.004). Grade 1 or more pigmentation developed at 1.5% (1 of 69) of dose points receiving less than 10 Gy vs. 25% (14 of 56) of dose points receiving more than 10 Gy (p < 0.001). A Grade 1 or more acute skin reaction was also significantly associated with development of Grade 1 or more pigmentation or telangiectasia at 60 months. This association was most significant for acute reaction and telangiectasia directly over the

  19. Including Exceptions: A System for Educating Students with Dual Sensory Impairments and Other Extreme Disabilities in General Education Settings. A Final Report.

    ERIC Educational Resources Information Center

    Ferguson, Dianne; And Others

    The Including Exceptions in Schools (IES) Project attempted to develop, implement, and validate a system for educating students with the most extreme dual sensory and other cognitive, physical, and health impairments in general education settings. The project involved 17 elementary and secondary students in Oregon, Idaho, and Louisiana over a…

  20. The Society for Vascular Surgery Lower Extremity Threatened Limb Classification System: risk stratification based on wound, ischemia, and foot infection (WIfI).

    PubMed

    Mills, Joseph L; Conte, Michael S; Armstrong, David G; Pomposelli, Frank B; Schanzer, Andres; Sidawy, Anton N; Andros, George

    2014-01-01

    Critical limb ischemia, first defined in 1982, was intended to delineate a subgroup of patients with a threatened lower extremity primarily because of chronic ischemia. It was the intent of the original authors that patients with diabetes be excluded or analyzed separately. The Fontaine and Rutherford Systems have been used to classify risk of amputation and likelihood of benefit from revascularization by subcategorizing patients into two groups: ischemic rest pain and tissue loss. Due to demographic shifts over the last 40 years, especially a dramatic rise in the incidence of diabetes mellitus and rapidly expanding techniques of revascularization, it has become increasingly difficult to perform meaningful outcomes analysis for patients with threatened limbs using these existing classification systems. Particularly in patients with diabetes, limb threat is part of a broad disease spectrum. Perfusion is only one determinant of outcome; wound extent and the presence and severity of infection also greatly impact the threat to a limb. Therefore, the Society for Vascular Surgery Lower Extremity Guidelines Committee undertook the task of creating a new classification of the threatened lower extremity that reflects these important considerations. We term this new framework, the Society for Vascular Surgery Lower Extremity Threatened Limb Classification System. Risk stratification is based on three major factors that impact amputation risk and clinical management: Wound, Ischemia, and foot Infection (WIfI). The implementation of this classification system is intended to permit more meaningful analysis of outcomes for various forms of therapy in this challenging, but heterogeneous population.